They come in limited quantities, depend on sky-high demand and stir speculative crazes in the secondary market.

它们数量有限，依赖于极高的需求，并在二级市场引发投机热潮。

The Food and Drug Administration permits limited quantities of insect parts to slip into foods during the manufacturing process.

美国食品和药物管理局允许在制造过程中将有限数量的昆虫部分放入食品中。

On the other hand, the ordinary belief that the amount of possible variation is a strictly limited quantity, is likewise a simple assumption.

另一方面，可能的变化量是严格受限的普通信念同样是一个简单的假设。

It has often been asserted, but the assertion is incapable of proof, that the amount of variation under nature is a strictly limited quantity.

人们经常断言， 但这种断言无法证明， 自然界的变异量是一个严格有限的数量。

There are some sorts of rude produce which nature has rendered a kind of appendages to other sorts; so that the quantity of the one which any country can afford, is necessarily limited by that of the other.

有一些种类的粗产物，自然使它们成为其他种类的附属物；因此，任何国家都能负担得起的数量必然受到另一个国家的限制。