| 单词 | spermatozoon |
| 例句 | The spermatozoa themselves may well be affected by loss of ATP. Silent Spring 1962-09-27T00:00:00Z There was a gasp, a murmur of astonishment and horror; a young girl screamed; standing on a chair to get a better view some one upset two test-tubes full of spermatozoa. Brave New World 1932-01-01T00:00:00Z Under the microscopes, their long tails furiously lashing, spermatozoa were burrowing head first into eggs; and, fertilized, the eggs were expanding, dividing, or if bokanovskified, budding and breaking up into whole populations of separate embryos. Brave New World 1932-01-01T00:00:00Z It horrifies me to think that about fourteen years ago the spermatozoon that turned into me shot out of that. Black Swan Green 2006-04-10T00:00:00Z I went to see a fertility specialist who told me that despite my less-than-stellar spermatozoa, the field of fertility, as it relates to the mumps, is somewhat of a mystery. Pushed Into the Future When Illness Strikes (in an Unlikely Place) 2017-03-17T04:00:00Z You let him wear sideburns, one shaped like larva and the other spermatozoa. Confirm or Deny: Laurie Metcalf 2019-04-13T04:00:00Z “Sperm competition” is the catch-all phrase for the myriad ways that male spermatozoa rival each other for the victory of fertilization — or at least to prevent other males’ sperm from doing so. 9 things you might not know about infidelity 2015-07-08T04:00:00Z “It was a race to be first that made you who you are,” a 1994 ad for Global Village proclaimed, with copy slapped over a fleet of high-resolution spermatozoa. On Reading Issues of Wired from 1993 to 1995 2016-06-07T04:00:00Z "The Daily Show's" humor would be funny enough even if it weren't true, but truth is satire's spermatozoon, and where it lands it leaves us not only laughing but thinking. Vintage chat: Moyers and Stewart 2011-05-18T16:30:00Z Silverman fixates on abortion for a long stretch, and brings up a fact that she’s recently learned: spermatozoa have a sense of smell. Sarah Silverman’s Comedy Is Changing with the Times 2017-06-01T04:00:00Z Are your spermatozoa wagging their flagella as if they can’t wait to get to that ovum – or listlessly floating around like dead tadpoles in a poorly executed classroom experiment? The rise of Big Sperm: does the tech world have the answer to our semen crisis? 2019-07-07T04:00:00Z Mature spermatozoa are characterized by an head, midpiece and a long tail for locomotion. Possible cause of male infertility 2023-10-27T04:00:00Z Ejection of spermatozoa may be a timed and coordinated event, as seen in certain species. Fundamentals of Biology 2015-01-01T00:00:00Z Converting these cells into viable spermatozoa could help to save the critically endangered animal from extinction. Science News Briefs from around the World: February 2023 2023-01-29T05:00:00Z The fifth stage of germ cell formation—spermatozoa, or formed sperm—is the end result of this process, which occurs in the portion of the tubule nearest the lumen. Anatomy and Physiology 2013-06-19T00:00:00Z The Oklahoma measure defines fertilisation as the "fusion of a human spermatozoon with a human ovum". Oklahoma passes bill banning most abortions after conception 2022-05-19T04:00:00Z Some are revealed to have long, squiggly tails — spermatozoa, perhaps, which resonate against the labial form that Rist designed for the lights. Review: Forget about 'immersive' Van Gogh. Pipilotti Rist's MOCA show is the real thing 2021-09-20T04:00:00Z The Sun Journal reports that James Howaniec wrote in a defense motion that the crime scene was “badly botched,” the investigation was flawed, and that the only physical evidence consists of “few spermatozoa molecules.” Defense seeks to have cold case charges tossed in Alaska 2019-11-27T05:00:00Z The carriers of Epstein’s apparently rarefied spermatozoa wouldn’t be the younger, underage sexual partners he allegedly prefers. Opinion | Jeffrey Epstein is a perversely tragic figure 2019-08-02T04:00:00Z The fluids improve the motility of the spermatozoa. Anatomy and Physiology 2013-06-19T00:00:00Z Some artists rendered the fireworks as feathery plumes, others as squiggly spermatozoa. Perspective | Remembering when emperors planned their own extravagant fireworks displays 2019-07-03T04:00:00Z This distribution was expected and confirms that the heterozygous patient sperm sample contained equal numbers of wild-type and mutant spermatozoa with similar motility and fertilization efficiency. Correction of a pathogenic gene mutation in human embryos : Nature : Nature Research 2017-08-01T04:00:00Z In the presence of fibrils, spermatozoa were slower. Protein tangles behind Alzheimer’s disease may be critical for human reproduction 2017-07-11T04:00:00Z “Our results demonstrate that generating human or domestic animal offspring from space-preserved spermatozoa is a possibility, which should be useful when the ‘space age’ arrives.” Space sperm produces healthy mice, raising prospect of future human settlement 2017-05-22T04:00:00Z While he might not be a household name today, the Dutch textile salesman ground and polished his own lenses, and was the first human to discover the existence of bacteria, single celled creatures, and spermatozoa. New Google Doodle Celebrates Antoni van Leeuwenhoek 2016-10-23T04:00:00Z The study, published in The Lancet Infectious Diseases, found the virus in about 4 percent of the spermatozoa of a 32-year-old man who had had Zika symptoms more than four months earlier. Children Who Get Zika After Birth Tend Not to Fall Seriously Ill, Study Finds 2016-09-30T04:00:00Z For, what were the spermatozoa he saw in his microscope if not little animalcules? This is how science lost God: Atheism, evolution and the long road to Richard Dawkins’ latest Twitter controversy 2016-01-17T05:00:00Z The previous oldest examples are collembolan spermatozoa found entombed in amber from the Late Eocene period, and crustacean sperm from cave deposits found in Australia. Fossilised sperm found in Antarctica is world's oldest, say scientists 2015-07-14T04:00:00Z The mobile H.I.V.-test Land Rover is painted with spermatozoa, all of them racing for the gas tank inlet. Three Approaches to Beating the AIDS Epidemic in South Africa 2014-08-25T04:00:00Z By the time a man turns 40, on the other hand, his gonad cells will have divided 610 times to make spermatozoa. Opinion: Why Fathers Really Matter 2012-09-08T21:03:01Z On Thursday, French researchers reported that the virus can penetrate individual spermatozoa. Children Who Get Zika After Birth Tend Not to Fall Seriously Ill, Study Finds 2016-09-30T04:00:00Z On the other hand, if any member of the class of spermatozoa containing the defective X fertilizes an egg two X-elements are brought together and this of itself means femaleness. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z The spermatozoa carry the infection to the maternal ovum. Essays In Pastoral Medicine 2012-03-05T03:00:09.993Z He attributed these to the fact that no two ova, no two spermatozoa, can be identical, since the process of nutrition cannot be absolutely alike. Herbert Spencer 2012-02-29T03:00:20.773Z The male ducts often have glandular walls, secreting capsules or spermatophores within which the spermatozoa are packed for transference to the female. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z In all probability it is, above all, essential, in order that it should occur, that one or more spermatozoa should penetrate the ovum. Fruits of Philosophy A Treatise on the Population Question 2011-12-03T03:00:10.910Z And the bulk of the nucleus in the spermatozoon consists of the chromosomes or their products. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z A line of 18 human spermatozoa would reach only across the head of an ordinary pin. Essays In Pastoral Medicine 2012-03-05T03:00:09.993Z Most ova are very minute cells, often microscopically minute, and a spermatozoon may be only 1/100,000th of the ovum's size—inconceivably minute, but yet exceedingly real and potent. Herbert Spencer 2012-02-29T03:00:20.773Z A, of Helix; B, of Eolis; a, ova; b, developing spermatozoa; c, common efferent duct. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5 "Gassendi, Pierre" to "Geocentric" 2011-09-02T02:00:20.450Z It is essentially necessary for fecundation that the spermatozoa should come into actual contact with the ovum. Fruits of Philosophy A Treatise on the Population Question 2011-12-03T03:00:10.910Z In some forms, moreover, the broader fundamental features of embryogeny are already established before the entrance of the spermatozoon. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z These spermatozoa have the power of locomotion in alkaline fluid. Essays In Pastoral Medicine 2012-03-05T03:00:09.993Z We are not at present concerned with the precise number of determinants, but we can see no reason why a spermatozoon should not contain millions if they were needed. Herbert Spencer 2012-02-29T03:00:20.773Z For these reasons, ova and spermatozoa can arise only when the germplasm which has been handed on from the original nucleus to certain cells is able to overcome the histogenous plasm of these cells. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Some attempts have been made in this laboratory to determine the effects of the freezing procedures on the metabolic activity of bull spermatozoa. Preservation of Bull Semen at Sub-Zero Temperatures 2011-08-13T02:00:22.680Z The outcome is that two corresponding classes of spermatozoa are produced. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z The human spermatozoon consists of a flattened head which has a thin protoplasmic cap extending down two-thirds of its length. Essays In Pastoral Medicine 2012-03-05T03:00:09.993Z Mature ova or spermatozoa will not normally divide if left to themselves, but that is because they are specialised to secure amphimixis, not because their powers are in any way declining or impoverished. Herbert Spencer 2012-02-29T03:00:20.773Z In many cases the spermatozoa of one species will not impregnate the eggs of another species. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z The spermatozoon is also like that of other animals, consisting of a rounded head and a lash-like tail, the movements of which enable it to move rapidly through the water. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z This would afford abundant opportunity for alcohol to act directly on the spermatozoon or the ovum. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z The human spermatozoon is only fifty-four thousandths of a millimetre in length, and from forty-one to fifty-three thousandths of a millimetre are taken up by its flagellum. Essays In Pastoral Medicine 2012-03-05T03:00:09.993Z In the history of the male element or spermatozoon, there is an analogous reduction, so that when spermatozoon and ovum unite in fertilisation the normal number is restored. Herbert Spencer 2012-02-29T03:00:20.773Z In other cases, the alien spermatozoon may penetrate the egg and unite with its nucleus, making, however, an unsatisfactory combination in various degrees of infertility. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z The spermatozoa resemble those of other animals, each possessing a head, which is shaped like an acorn, and a long vibratile tail by means of which it moves through the water. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z It has been clearly demonstrated in several cases that eggs fertilized by spermatozoa which possess this X-element, always become females, those fertilized by spermatozoa which do not possess it always develop into males. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z The blastomeres in the human ovum may perhaps be injured in part by toxins from the mother, or they may be defective through disease in the ovum or the spermatozoon. Essays In Pastoral Medicine 2012-03-05T03:00:09.993Z In the spermatozoa of the male is the first evolution of the organic life of the planet. The Universe a Vast Electric Organism 2011-06-09T02:00:22.450Z The process begins with the fertilisation of the egg-cell by the fusion with its nucleus of the nucleus or head of a male-cell or spermatozoon. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z The egg of Hydra is said to be fertilized as it lies at the base of the ectoderm, through which the fertilizing spermatozoon bores its way. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z Half of the spermatozoa therefore will bear an x-element, half will be without it. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z The reproductive cell produced by the male is called the spermatozoon, and that produced by the female, the ovum. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z The spermatozoa exhibit many differences in shape, size and proportions, in the various groups of birds. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z So far as microscopical characters go, egg cells and spermatozoa are wonderfully alike in all the mammalia; in many cases we could not distinguish between those of different animals. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z Most, if not all species are hermaphrodite, eggs and spermatozoa being produced either simultaneously or in succession by each individual, or by certain individuals in each zoarium. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z Thus normally only one spermatozoon unites with an egg. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z It has been observed in some eggs that a membrane, formed round the ovum immediately after the entrance of the spermatozoon, prevents the entrance of others. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z Moreover, there is a significant agreement in the character of the spermatozoa of Limulus and Scorpio. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 3 "Apollodorus" to "Aral" The hereditary masses contained in the egg and spermatozoon can be composed only of such particles as are the bearers of cell-characters. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z In Calcutta both eggs and spermatozoa are produced at all times of the year simultaneously in the same zoœcia, but the eggs in one zoœcium often vary greatly in size. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z And it is a very significant fact that while the ovum and spermatozoon are very unequal in size themselves, the chromosomes of the two germ-cells are of the same size and number. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z If Gametogeny. than one spermatozoon enters, a corresponding number of male pronuclei are formed, and the subsequent development, if it takes place at all, is abnormal and soon ceases. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z The ovum may remain for a period, and the spermatozoa that seek the ovum may enter, but neither may tarry unless each yields itself to the other in that mysterious union which results in life. What a Young Husband Ought to Know Characters appropriate both to males and to females are transmitted either by eggs or by spermatozoa. The Biological Problem of To-day Preformation Or Epigenesis? The Basis of a Theory of Organic Development 2011-08-29T02:01:04.170Z It is not known whether the eggs of sponges are fertilized by spermatozoa from the individual that produces the egg or by those of other individuals, but not improbably both methods of fertilization occur. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z The spermatozoa of most animals are of linear form, each with a head, a middle-piece and a long vibratile tail which is used for locomotion. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z Each spermatid becomes a functional spermatozoon or male gamete. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z When we come to the spermatozoa, or sperm, of the male, we find an entirely different manifestation. What a Young Husband Ought to Know The ova and the spermatozoa dehisce into the body cavity and pass to the exterior through the nephridia. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 3 "Borgia, Lucrezia" to "Bradford, John" The contents of these cells divide and subdivide in such a way that they finally consist of a mass of spermatozoa surrounded by a single covering cell, which they finally rupture, and so escape. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z In a few forms an interesting reversal of conditions has been found in that the eggs instead of the spermatozoa show the characteristic dimorphism. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z As this is in all probability derived entirely from the nucleus of the spermatozoon, we should be almost justified in calling the nucleus of the spermatozoon the male pronucleus. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z The spermatozoa enter it and pass through its walls and traverse a minute duct formed of two accessory cells, and finally enter the ripe ovum. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 7 "Cerargyrite" to "Charing Cross" The deeper part contains the spermatozoa, the external part is called the connective, and is usually much contracted and spirally 692 coiled. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 6 "Celtes, Konrad" to "Ceramics" The cells from which those of the gemmules are derived are akin in origin to those that give rise to eggs and spermatozoa. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z When mature these small flagellate cells, now known as spermatozoa, escape into the interior of the parent colony and swim about actively. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z There is reason to believe that the same assertion may be made of spermatozoa. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z These break off and, lying in the coelomic fluid, break up into spermatozoa. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 7 "Cerargyrite" to "Charing Cross" This principle consists of a fluid in which float tiny little creatures called spermatozoa—one is a spermatozoon. Almost a Woman Each consists of a mass of sperm-mother cells, in which the spermatozoa originate in large numbers. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z As soon as the nucleus of the spermatozoon, now known as the male pronucleus, reaches the interior of the egg, it enlarges and becomes similar in appearance to the female pronucleus. Being Well-Born An Introduction to Eugenics 2012-05-22T15:16:53.140Z Gametogeny is the name applied to the formation of the gametes, i.e. of the ova and spermatozoa. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z One of the spermatozoa, or germs of life, much magnified. The Sex Side of Life An Explanation for Young People You can understand that, for the spermatozoa to be placed where they can find their way into the uterus, means a very close and familiar relation of the man and woman. Almost a Woman In the cells of the spermary the spermatozoa are closely packed together, with their heads pointing outwards towards the summit of the mound through which they finally make their way into the water. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z The membrane of the vesicul� seminales is formed of circular fibres; and is, I presume, contractile, for I have seen the spermatozoa expelled with force from the cut end of a living specimen. A Monograph on the Sub-class Cirripedia With Figures of all the Species. As soon as the spermatozoon has conjugated with the ovum, a second nucleus appears in the ovum. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z As in the species previously described the spermatozoa are evidently dimorphic. Studies in Spermatogenesis Part II The formation of the spermatozoa is peculiar in that the original spermatocyte cell-body, as a rule, does not divide; but the four nuclei resulting from the two maturation divisions develop into sperm-heads in one cell. Studies in Spermatogenesis Part I The minute organism was colourless, transparent, considerably larger than the spermatozoa of Hydra, slightly constricted in the middle and rounded at each end. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z In the one specimen preserved in spirits, I unfortunately omitted to search for the vesicul� seminales; I cannot doubt that such existed, but it would have been important to have ascertained whether they contained spermatozoa. A Monograph on the Sub-class Cirripedia With Figures of all the Species. This is undoubtedly derived from the spermatozoon, possibly from its nucleus only, and is called the male pronucleus. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z In all of these insects the spermatozoa are distinctly dimorphic, forming two equal classes, one of which either contains one smaller chromosome or lacks one chromosome. Studies in Spermatogenesis Part II The egg is a cell, and the spermatozoon is a cell. A Critique of the Theory of Evolution Eggs and spermatozoa are produced in great numbers, as a rule simultaneously in the same zoœcia, but individuals kept in captivity often produce spermatozoa only. Freshwater Sponges, Hydroids & Polyzoa 2011-06-25T02:00:17.833Z This bag contained either pulpy matter, or a great mass of spermatozoa. A Monograph on the Sub-class Cirripedia With Figures of all the Species. In normal fertilization, as a rule, only one spermatozoon fuses with the ovum. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 3 "Electrostatics" to "Engis" 2011-02-06T03:00:53.093Z The female cell is always much larger than the male; where the former is swollen with the reserve food, the spermatozoa may be less than a millionth of its volume. The Truth About Woman This results chiefly from catarrh and inflammation which destroy the spermatozoa before they can reach the egg during its descent. The Sexual Question A Scientific, psychological, hygienic and sociological study They are called spermatozoa, or each one is a spermatozoon. Almost A Man I compared these spermatozoa with others taken out of the vesicul� seminales of the individual hermaphrodite S. vulgare, to which the parasite was attached, and could not perceive the slightest difference in them. A Monograph on the Sub-class Cirripedia With Figures of all the Species. The rate of the segmentation is likewise determined by the number of the spermatozoa. The Variation of Animals and Plants Under Domestication, Volume II (of 2) Among animals the female contributes the ovum and the male the spermatozoon; among plants the corresponding cells are the ovules and pollen grains. Mendelism Third Edition It proves that the spermatozoa arrive at their goal even when the womb is entirely passive. The Sexual Question A Scientific, psychological, hygienic and sociological study Each one contains in itself all the particular traits, characteristics or talents which the father would confer on the child of which this spermatozoon would form a part. Almost A Man The full development of the spermatozoa consumes, I suppose, some considerable lapse of time. A Monograph on the Sub-class Cirripedia With Figures of all the Species. The belief that it is the function of the spermatozoa to communicate life to the ovule seems a strange one, seeing that the unimpregnated ovule is already alive and continues for a considerable time alive. The Variation of Animals and Plants Under Domestication, Volume II (of 2) When this happens an ovum of any one of the four types has an equal chance of being fertilised by a spermatozoon of any one of the four types. Mendelism Third Edition Spermatozoa and Ova.—In all the higher animals, including the hermaphrodites, the male germinal cells, or spermatozoa are characterized by their mobility. The Sexual Question A Scientific, psychological, hygienic and sociological study In this relation the spermatozoon of the man unites with the germ or ovum of the 17 woman and a new life is begun. Almost A Man The thorax, into which I traced the vesicula seminalis, no doubt also serves for the emission and first direction of the spermatozoa; and hence, perhaps, its singularly extensible structure. A Monograph on the Sub-class Cirripedia With Figures of all the Species. In these several cases, the spermatozoa and pollen-grains must exist in considerably larger numbers. The Variation of Animals and Plants Under Domestication, Volume II (of 2) We are led, therefore, to suppose that an ovum carrying the yellow factor is unproductive if fertilised by a spermatozoon which also bears this factor. Mendelism Third Edition The spermatozoa of alcoholics suffer like the other tissues from the toxic action of alcohol on the protoplasm. The Sexual Question A Scientific, psychological, hygienic and sociological study One variety of these cells, the spermatogonia, undergo an increase of size at puberty, and from these spermatogonia, after passing through several intermediate transitional stages, the spermatozoa are formed. The Sexual Life of the Child It is also probable, that the action of the cirri of the hermaphrodite, would tend to draw inwards the spermatozoa in the right direction. A Monograph on the Sub-class Cirripedia With Figures of all the Species. These almost infinitely numerous and minute gemmules must be included in each bud, ovule, spermatozoon, and pollen-grain. The Variation of Animals and Plants Under Domestication, Volume II (of 2) In concept the seed corn has the same value as the spermatozoon. Hidden Symbolism of Alchemy and the Occult Arts The duty of the active or male individual is to bring the spermatozoa to a point where they can easily reach the female cells or ovules. The Sexual Question A Scientific, psychological, hygienic and sociological study The spermatozoa first make their appearance during that year of life which is usually regarded as the year of the puberal development. The Sexual Life of the Child In the parasitic complemental male of S. vulgare, I also most plainly saw spermatozoa. A Monograph on the Sub-class Cirripedia With Figures of all the Species. Carefully nursing the frail embryo he added other plasms, then fertilized the whole with warm spermatozoa and placed it in the incubator over which glowed a violet, radio-active light. Omega, the Man It is well known how Weismann was led, by his hypothesis of the continuity of the germ-plasm, to regard the germinal cells—ova and spermatozoa—as almost independent of the somatic cells. Creative Evolution The Male or Papa Egg.—The male or papa egg is called a "spermatozoa." The Eugenic Marriage, Vol. 2 A Personal Guide to the New Science of Better Living and Better Babies The spermatozoa may be first formed at very varying ages. The Sexual Life of the Child The reader will remember, however, from the chapter on Reproduction, that the contribution of the spermatozoa only initiates the sacrifices that the paternal organism must make in this process. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male But we are still some way off any assurance that the main object of the spermatozoon in inducing the development of the egg is this surface alteration. Science and Morals and Other Essays They have succeeded in developing embryos from the eggs of the sea urchin, of the nereis, and of mollusks, without spermatozoa. Northern Nut Growers Association, Report of the Proceedings at the Third Annual Meeting Lancaster, Pennsylvania, December 18 and 19, 1912 Emphasize to your daughter that the female ovule or egg, and the male egg, or spermatozoa, are minute objects, so microscopically small that a hundred million of them could comfortably lie upon a ten-cent piece. The Eugenic Marriage, Vol. 2 A Personal Guide to the New Science of Better Living and Better Babies Haberda is of opinion that, speaking generally, the first formation of the spermatozoa is associated with the appearance of the other indications of puberty. The Sexual Life of the Child The formation and release of spermatozoa is only slightly modified by the condition of nutrition; while the rate of secretion from the vesicles is greatly modified in quantity. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male Above all we are entitled to ask why there are any effects, or even why there is any ovum or any spermatozoon or curious physiological investigator, to give the artificial stimulus. Science and Morals and Other Essays Pronucleus: the nucleus of male and female elements, spermatozoa and ova, the union of which forms the nucleus of a fertilized ovum. Explanation of Terms Used in Entomology The Function of the Spermatozoa.—God gave the male spermatozoa the power to move. The Eugenic Marriage, Vol. 2 A Personal Guide to the New Science of Better Living and Better Babies The secondary sexual characters are, therefore, independent of the formation of spermatozoa, and the appearance of these characters must depend upon other processes, occurring much earlier in life. The Sexual Life of the Child The spermatozoa are very sensitive to acid and their vitality is seriously impaired by acid of any kind, particularly the acid of the urine. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male The eggs are indifferent and the spermatozoa are each male, or female. Evolution in Modern Thought Male: that sex having organs for the production of spermatozoa: designated by "?", the astronomical sign for Mars. Explanation of Terms Used in Entomology The best way to explain the brief activity to your daughter, is to liken the spermatozoa, to a mechanical toy, which is wound up to go for a certain time. The Eugenic Marriage, Vol. 2 A Personal Guide to the New Science of Better Living and Better Babies Thus, the effects of castration are due, on this theory, not to the absence of the formation of spermatozoa, but to the absence of the products of the interstitial glands. The Sexual Life of the Child It is not likely that any great number of spermatozoa are released, those that are probably make their way along the vasa deferentia to the ampullæ. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male Owing to the immense size of its spermatozoa, it has rendered great aid to embryology, a science which, when understood au fond, will bring about great changes in the human race. Memoirs For if two or more spermatozoa got into the same ovum a monstrosity would be apt to be the result. Woman Her Sex and Love Life It is by this act that the male spermatozoa is enabled to complete the function of fecundation. The Eugenic Marriage, Vol. 2 A Personal Guide to the New Science of Better Living and Better Babies The cells of this epithelium have their internal borders differentiated into spermatozoa, which, at a subsequent stage, are liberated. Text Book of Biology, Part 1: Vertebrata The egg is very much larger than the spermatozoon, and contains enough yolk material to afford nourishment for the embryo for a number of days. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male The spermatozoon fertilises the ovum, introducing 2 chromosomes. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told And as the spermatozoa carry in them the entire impress of the man, and the ova of the woman, they foretell us the fates of the future boy and girl. Woman Her Sex and Love Life So has the spermatozoa, and by the incessant movement of this microscopic tail they all move upward as soon as discharged by the male. The Eugenic Marriage, Vol. 2 A Personal Guide to the New Science of Better Living and Better Babies Fertilization is effected by a spermatozoon meeting with the ovum. Text Book of Biology, Part 1: Vertebrata The spermatozoa frequently remain several days in the organs of the female before the ovum is found and fertilized. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male The centrosome introduced by the spermatozoon has divided into two centrosomes, one at each pole of the nucleus. The Outline of Science, Vol. 1 (of 4) A Plain Story Simply Told Many of the spermatozoa, weaker than the others, perish on the way, and only a few continue the journey up through the uterus to the tube. Woman Her Sex and Love Life The shape of the male principle, or spermatozoa, is exactly like a little tadpole, and you no doubt recall that a tadpole has a minute tail, the movement of which enables it to swim around. The Eugenic Marriage, Vol. 2 A Personal Guide to the New Science of Better Living and Better Babies The character of the essential male element, the spermatozoon, the general nature of the reproductive process, will be conveniently deferred until the chapters upon development are reached. Text Book of Biology, Part 1: Vertebrata While the parental sacrifice in eggs or spermatozoa is minute and inconsiderable in the higher animals, the sacrifices subsequent to this initial division are incalculably greater in higher animals than in the lower organisms. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male Certain cells of the fleshy pulp assume the character of ova, and others that of spermatozoa. The Handy Cyclopedia of Things Worth Knowing A Manual of Ready Reference If it does contain a normal number of lively, rapidly moving spermatozoa, the man is fertile, regardless of whether he ever had epididymitis or not. Woman Her Sex and Love Life The spermatozoa do not have time to become maturely developed. Plain Facts for Old and Young The whole body of the babe is developed from the ovum or female element after it has been fertilized by the spermatozoon or male element. Herself Talks with Women Concerning Themselves So far as physiologists know at present, the external secretion differs from the internal secretion only in possessing spermatozoa. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male Dr. Bertholet made a microscopic examination of the reproductive glands of 75 chronic male alcoholics, and in 37 cases he found them more or less atrophied, and devoid of spermatozoa. Applied Eugenics The spermatozoa are capable of independent motion, and they travel pretty fast. Woman Her Sex and Love Life The composition of the nerves and that of spermatozoa is nearly identical. Plain Facts for Old and Young Here it remains if it is impregnated or fertilized by a union with the spermatozoon or male element. Herself Talks with Women Concerning Themselves During these several days the spermatozoa are exerting no small amount of energy in their vigorous flagellate movement. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male Several days may elapse before the spermatozoa meet with an ovum and fertilize it. Aids to Forensic Medicine and Toxicology When a man has discharged his spermatozoa his work is done—the woman's only commences. Woman Her Sex and Love Life Development still continues, until finally the thin pellicle on the outside of the bundle is ruptured, thus liberating the young spermatozoa, which speedily complete their full development. Plain Facts for Old and Young Thus it comes about that each of the sexual elements, the egg and the spermatozoon, now contains one half the normal number of chromosomes. The Story of the Living Machine A Review of the Conclusions of Modern Biology in Regard to the Mechanism Which Controls the Phenomena of Living Activity The spermatozoa, together with a small amount of the liquid secretion, will make their way gradually along the vasa deferentia and collect in the ampullæ. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male For according to Mr. Spencer's theory, it is the instinct that is weakened not the power of the spermatozoa to fertilize. The Fertility of the Unfit For it is they that generate the eggs, or ova, or ovules, which, after becoming fertilized or fecundated by the spermatozoa of the male, develop into children. Woman Her Sex and Love Life In man, the formation of spermatozoa continues with greater or less rapidity from puberty to old age, though at the two extremes of existence they are imperfectly developed. Plain Facts for Old and Young Previously to this process the other sexual cell, the spermatozoon, or male reproductive cell, has been undergoing a somewhat similar process. The Story of the Living Machine A Review of the Conclusions of Modern Biology in Regard to the Mechanism Which Controls the Phenomena of Living Activity Within these lobules the spermatozoa are formed by a complex process of cell division and cell germination upon whose description we need not enter here. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male From these two elements, the spermatozoa, or male element, and the ova, or female element, all life, except in the lowest organisms, is produced. The Power of Womanhood, or Mothers and Sons A Book For Parents, And Those In Loco Parentis The condition of the germ-plasms, i.e., the condition of the ovum and the spermatozoa at the time of conception is more important than all subsequent care during gestation. Woman Her Sex and Love Life In the ova of certain fishes, small openings have been observed through which the spermatozoa find entrance. Plain Facts for Old and Young As organisms rise in the scale it seems natural that the male should carry the spermatozoa to the females in his own body. Alfred Russel Wallace: Letters and Reminiscences, Vol. 1 The small advance guard of spermatozoa that may have made their way to the ampullæ will undergo a gradual decrease of their nascent activity, as the days go by. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male When we turn to the starting point of human development, we find an egg cell and a spermatozoon, which unite and whose nuclei intermingle. Scientific American Supplement, No. 810, July 11, 1891 An extreme degree of anteversion or anteflexion, or retroversion or retroflexion, may interfere with impregnation, as the spermatozoa may find it difficult or impossible to reach the opening of the womb—the external os. Woman Her Sex and Love Life Human spermatozoa are about 1/600 of an inch in length. Plain Facts for Old and Young Under all conditions, the sex is determined by a struggle for the mastery in the egg-cell, between the energy of that egg-cell and the energy of the male spermatozoon. Valere Aude Dare to Be Healthy, Or, The Light of Physical Regeneration The spermatozoon may be described as the male sexual cell whose function is to fertilize the female ovum. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male We have here evidently a process corresponding to the fertilization of the egg in higher animals; yet there is no egg, spermatozoon, or sex. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 But a glass of wine at a wedding banquet cannot affect the previously formed spermatozoa. Woman Her Sex and Love Life In certain parts, probably, of all plants, are found peculiar spiral filaments, having a striking resemblance to the spermatozoa of animals. COSMOS: A Sketch of the Physical Description of the Universe, Vol. 1 The total length of the spermatozoon is only about 1/300 of an inch, and 4/5 of this is the tail. Taboo and Genetics A Study of the Biological, Sociological and Psychological Foundation of the Family The spermatozoon is about 1/20 of an inch in length and consists of a head, body and a vibratile tail. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male It is a little mass of protoplasm containing a nucleus, and corresponds, therefore, to one of the cells, most closely to the egg-cell or spermatozoon of higher animals. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 When sterility is due to a defect in the husband's spermatozoa, and is not discovered, as it usually might be, before marriage, the question of impregnating the wife by other methods has occasionally arisen. Studies in the Psychology of Sex, Volume 6 Sex in Relation to Society Its significance is not alone for the race, it is not simply concerned with the formation of the spermatozoa which share equally with the ova the honor of making the mankind of the future. Studies in the Psychology of Sex, Volume 5 Erotic Symbolism; The Mechanism of Detumescence; The Psychic State in Pregnancy Those from the male are called sperms or spermatozoa and those from the female eggs or ova. Taboo and Genetics A Study of the Biological, Sociological and Psychological Foundation of the Family In the human spermatozoon the head is ovoid, appearing pear-shaped or pointed in one view and elliptical in another. The Biology, Physiology and Sociology of Reproduction Also Sexual Hygiene with Special Reference to the Male It had long been known that all higher forms start in life as single cells, egg and spermatozoon. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 This element is technically known as a sperm, or a spermatozoa. Sane Sex Life and Sane Sex Living Some Things That All Sane People Ought to Know About Sex Nature and Sex Functioning; Its Place in the Economy of Life, Its Proper Training and Righteous Exercise She knew, though she had never heard such a word as spermatozoa. The Pretty Lady Loeuwenhoek's development of the microscope in the 17th century led immediately to the discovery of the spermatozoon by one of his students. Taboo and Genetics A Study of the Biological, Sociological and Psychological Foundation of the Family The germ acts on the cell, as Lancereaux has pointed out, in the same way as a spermatozoon. The Inferno Through these also the eggs and spermatozoa are discharged. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 There was also a point striking deep in the debate on Professor Loeb's experiments with sea urchins; how far had he succeeded in reproducing the species without the male spermatozoa? Scott's Last Expedition Volume I The ova consist of spherical cells, while the spermatozoa resemble an arrow-head in shape. Scientific American Supplement, No. 601, July 9, 1887 Leuwenhoek's discovery of the spermatozoa furnished a welcome confirmation for this doctrine, that all individuals have existed since the beginning of the world, at least as preformed germs. History of Modern Philosophy From Nicolas of Cusa to the Present Time Upon fertilization with spermatozoa, in normal sea water, they proceed again to develop. Popular Science Monthly Oct, Nov, Dec, 1915 — Volume 86 Here they are nourished by the other cells and develop into true reproductive elements, eggs and spermatozoa. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 The parthenogenetic ovum of the bee is male, and yet it is an ovum capable only of producing spermatozoa. Hormones and Heredity These secretions destroy the vitality of the spermatozoa, and this condition may be considered a common cause of sterility in the larger animals. Common Diseases of Farm Animals The cell contributed by the mother is called an egg- cell or ovum; that contributed by the father, a spermatozoon. The Prospective Mother, a Handbook for Women During Pregnancy The cells which live naturally isolated in the organism, such as the corpuscles of the blood and spermatozoa, were the first studied. The Great Events by Famous Historians, Volume 21 The Recent Days (1910-1914) Fertilization, that is, the union of egg and spermatozoon, or mainly of their nuclei, takes place; and the fertilized egg develops into a new organism. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 Castration during the breeding season causes the external pigmented layer with its papillae to be cast off very soon—that is to say, it has the same effect as the normal discharge of the spermatozoa. Hormones and Heredity After the operation, the germinal cells, which grow into the spermatozoa, atrophy and disappear, since they can no longer function. The Glands Regulating Personality This vital stimulus can be imparted only by the spermatozoon. The Prospective Mother, a Handbook for Women During Pregnancy Here, in all these cases, what is required is the detachment of two portions of the parental organisms, which portions we know as the egg or the spermatozoon. Darwiniana : Essays — Volume 02 On account of mutual attraction they unite in the reproductive glands to form eggs or spermatozoa. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 In June and July spermatogenesis is active, and from August to October the formation of ripe spermatozoa is completed. Hormones and Heredity From the moment when the spermatozoon penetrates and fecundates the ovum, the fate of the future being is settled by their disposition. The Glands Regulating Personality We have seen that the spermatozoon represents the solitary contribution of the father toward the development of the child, and the spermatozoon, therefore, must convey the material basis of paternal inheritance. The Prospective Mother, a Handbook for Women During Pregnancy A piece of the paternal soul goes with-the spermatozoon, and a piece of the mother's soul remains in the ovum. The Evolution of Man — Volume 2 The eggs and spermatozoa of two such individuals might not infrequently unite, and thus in time the two characteristics be inherited by a large fraction of the species. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 With regard to internal development, after the discharge of spermatozoa in the breeding season the spermatogonia divide and proliferate, forming groups of cells known as spermatocysts. Hormones and Heredity As they possess definite canals for the removal of their gross secretion, the specific reproductive cells, ova or spermatozoa, to a surface of the body, they are first of all glands of external secretion. The Glands Regulating Personality Almost at the moment when they touch, the two cells unite so intimately that all trace of the spermatozoon is lost. The Prospective Mother, a Handbook for Women During Pregnancy Thus the female salmon deposits her eggs on a convenient spot in the bed of a stream and the attendant male salmon then projects over them the spermatozoa. Men Women and God The fertilized egg-cell, formed by the union of egg and spermatozoon, is a single cell, like the individual resulting from the conjugation or fusion of two protozoa. The Whence and the Whither of Man A Brief History of His Origin and Development through Conformity to Environment; Being the Morse Lectures of 1895 The vasa deferentia were seen as white convoluted threads on the peritoneum, but contained no spermatozoa. Hormones and Heredity All our limbs and sensual organs, in fact, our whole body and life, are but an accretion round and a fostering of the spermatozoa. The Glands Regulating Personality FERTILIZATION.—Convincing observations upon the lower forms of life, especially upon fishes, have shown that when the germinal cells come near to each other, the ovum attracts the spermatozoon. The Prospective Mother, a Handbook for Women During Pregnancy The older theories of impregnation generally went astray in regarding the large ovum as the sole base of the new organism, and only ascribed to the spermatozoon the work of stimulating and originating its development. The Evolution of Man — Volume 1 The ova, spermatozoa and embryos not only of all human races but of all things that live, whether animal or vegetable, think little, but that little almost identically on every subject. The Note-Books of Samuel Butler The liquid pressed from this was swarming with spermatozoa in active motion. Hormones and Heredity Thus, young animals deprived of the pituitary will not, if male, grow spermatozoa, nor ripe ova in the female. The Glands Regulating Personality In man, for example, the addition of twenty-four chromosomes from the spermatozoon to an ovum that already contained twenty-four chromosomes of its own would mean that after fertilization the ovum contained forty-eight. The Prospective Mother, a Handbook for Women During Pregnancy And even when this had been demonstrated, the spermatozoon was believed to disappear in the ovum without leaving a trace. The Evolution of Man — Volume 1 All our limbs and sensual organs, in fact our whole body and life, are but an accretion round and a fostering of the spermatozoa. The Note-Books of Samuel Butler The X sex-chromosome is not in itself either female or male, since, as we have seen, either ovum or spermatozoon may contain a single X chromosome. Hormones and Heredity That gentleman himself remarks that spermatozoa, which belong to animal organisms, are insoluble in ammonia, the effect of which is merely to make them paler. The Harvard Classics Volume 38 Scientific Papers (Physiology, Medicine, Surgery, Geology) Such a result is prevented through the process to which we have referred in the preceding chapter as the ripening of the ovum, and also through a similar process in the case of the spermatozoon. The Prospective Mother, a Handbook for Women During Pregnancy The spermatozoa of the great majority of animals have two characteristic features. The Evolution of Man — Volume 1 The uncertainty becomes still greater owing to our inadequate knowledge as to the length of time during which the sexual elements, the ova and the spermatozoa, retain their vitality after liberation from their respective sources. The Four Epochs of Woman's Life; a study in hygiene In the earthworms, for instance, we have, in every individual developed from a zygote, ova and spermatozoa developing in different gonads in different parts of the body. Hormones and Heredity It is true one may argue that the zoospores of certain cryptogamia exhibit similar movements; but do not these zoospores possess as much of an animal nature as do the spermatozoa? The Harvard Classics Volume 38 Scientific Papers (Physiology, Medicine, Surgery, Geology) On the other hand, single ovum, or identical, twins are always of the same sex; this follows, since but one egg and but one spermatozoon are here concerned. The Prospective Mother, a Handbook for Women During Pregnancy The more Hertwig chloroformed the ovum, the more spermatozoa were able to bore their way into its unconscious body. The Evolution of Man — Volume 1 Third, do the secretions in the canal poison the spermatozoa? The Four Epochs of Woman's Life; a study in hygiene At this time each organ is almost as large as a pigeon's egg, is very soft, and the liquid exuding from it when cut is swarming with spermatozoa. Hormones and Heredity The nuptial flight places her permanently in possession, till death, of the spermatozoa torn from her unfortunate lover. The Life of the Bee More commonly their genesis depends upon the ripening of two eggs at about the same time and the fertilization of both by two different spermatozoa. The Prospective Mother, a Handbook for Women During Pregnancy Most of the earlier observers thought that the spermatozoon did not penetrate into the ovum. The Evolution of Man — Volume 1 The spermatozoon penetrates into the ovule and becomes fused with it. The Four Epochs of Woman's Life; a study in hygiene So that ovules, spermatozoa, and pollen-grains,—the fertilised egg or seed, as well as buds,—include and consist of a multitude of germs thrown off from each separate part or unit. The Variation of Animals and Plants under Domestication — Volume 2 As organisms rise in the scale it seems natural that the male should carry the spermatozoa to the female in his own body. More Letters of Charles Darwin — Volume 2 Longer but much narrower than the ovum, the tiny arrow-shaped spermatozoon is particularly distinguished by its active motility, for it has a tail that propels it. The Prospective Mother, a Handbook for Women During Pregnancy On the other hand, the next cell which we have to consider in the process of conception, the male sperm-cell or spermatozoon, is one of the smallest cells in the animal body. The Evolution of Man — Volume 1 But the other day I came to the conclusion that some day we shall have cases of young being produced from spermatozoa or pollen without an ovule. More Letters of Charles Darwin — Volume 1 The rate also of the segmentation of the ovum is determined by the number of the spermatozoa. The Variation of Animals and Plants under Domestication — Volume 2 I know it is not new; but how wonderful his account of the spermatozoa of some dioecious alga or conferva, swimming and finding the minute micropyle in a distinct plant, and forcing its way in! More Letters of Charles Darwin — Volume 2 Since only one spermatozoon enters the ovum, whether or not the child will be a boy or a girl depends entirely upon which type gains entrance. The Prospective Mother, a Handbook for Women During Pregnancy It bears in the cell and nuclear matter of the penetrating spermatozoon a part of the father's body, and in the protoplasm and caryoplasm of the ovum a part of the mother's body. The Evolution of Man — Volume 1 If I ask myself how you derive, and where you place the innumerable gemmules contained within the spermatozoa formed by a male animal during its whole life, I cannot answer myself. More Letters of Charles Darwin — Volume 1 These almost infinitely numerous and minute gemmules are contained within each bud, ovule, spermatozoon, and pollen-grain. The Variation of Animals and Plants under Domestication — Volume 2 I found spermatozoa, and spermatozoa only come from males. The Lani People Furthermore, since the facts indicate that male-producing and female-producing spermatozoa are present in equal numbers, it follows that practically there is an even chance that an embryo will develop into a boy or a girl. The Prospective Mother, a Handbook for Women During Pregnancy This tiny round corpuscle of chromatin now acts as a centre of attraction for the invading spermatozoon in the large ripe ovum, and coalesces with its "head," the male pro-nucleus. The Evolution of Man — Volume 1 The reader knows that the eggs of the overwhelming majority of animals cannot develop unless a spermatozoon enters them. Darwin and Modern Science He experimented with frogs, tortoises, and dogs; and settled beyond question the function of the ovum and spermatozoon. A History of Science — Volume 4 It was strange how so little a thing as the union of a spermatozoon and an ovum could produce so much trouble. The Lani People The animalculists held that the spermatozoa were the true germs, and appealed to the lively movements and the structure of these bodies. The Evolution of Man — Volume 1 But only one of these innumerable spermatozoa is chosen—namely, the one that first reaches the ovum by the serpentine motions of its tail, and touches the ovum with its head. The Evolution of Man — Volume 1 This suggests also the possibility that at that period outside forces may have supplied the conditions for the development of the egg which at present the spermatozoon has to supply. Darwin and Modern Science He showed convincingly that the development of every organism consists of a series of NEW FORMATIONS, and that there is no trace whatever of the complete form either in the ovum or the spermatozoon. The Evolution of Man — Volume 1 It inherits from the father by means of the spermatozoon, and from the mother by means of the ovum. The Evolution of Man — Volume 1 Moreover, we now know that these spermatozoa are not at all a peculiar form of cell; precisely similar cells are found in various other parts of the body. The Evolution of Man — Volume 1 It took a good deal of comparative research to convince us that each of these spermatozoa is really a simple cell. The Evolution of Man — Volume 1 It is thus unavoidable that at certain periods more than one kind of spermatozoon is suspended in the sea-water and it is a matter of surprise that the most heterogeneous hybridisations do not constantly occur. Darwin and Modern Science The sea-urchin eggs which were fertilised in the laboratory by the spermatozoa of the starfish, as a rule, died earlier than those of the pure breeds. Darwin and Modern Science It might be argued that in the case of heterogeneous hybridisation the sperm-nucleus does not fuse with the egg-nucleus, and that, therefore, the spermatozoon cannot transmit its hereditary substances to the larvae. Darwin and Modern Science It seemed necessary in these experiments to imitate as completely as possible by chemical agencies the effects of the spermatozoon upon the egg. Darwin and Modern Science In the previous illustrations we have distinguished in the spermatozoon a head, trunk, and tail. The Evolution of Man — Volume 1 The eggs are indifferent and the spermatozoa are each male, OR female. Darwin and Modern Science |
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