So, redheads have to be given more anaesthetics before surgery.

所以，红头发的人在手术前必须接受更多的麻醉。

Considering that safe anaesthetics and antibiotics were only discovered in the 19th and 20th centuries, it was a truly painful and risky business to go under the knife in the past.

考虑到安全的麻醉剂和抗生素是在 19 世纪和 20 世纪才被发现的，在过去动刀确实是一件痛苦和冒险的事情。