Chap. 49.] THE BEALN. 4J 



from their birth. 81 There are some animals, also, that are natu- 

 rally bald, such as the ostrich, for instance, and the aquatic 

 raven, which last has thence derived its Greek 82 name. It is 

 but rarely that the hair falls off in women, and in eunuchs 

 such is never known to be the case ; nor yet does any person 

 lose it before having known sexual intercourse. 83 The hair 

 does not fall off below the brain, nor yet beneath the crown of 

 the head, or around the ears and the temples. Man is the 

 only animal that becomes bald, with the exception, of course, 

 of such animals as are naturally so. Man and the horse are 

 the only creatures whose hair turns grey ; but with man this is 

 always the case, first in the fore-part of the head, and then in 

 the hinder part. 



CHAP. 48. THE BONES OF THE HEAD. 



Some few persons only are double- crowned. The bones of 

 the head are flat, thin, devoid of marrow, and united with su- 

 tures indented like a comb. "When broken asunder they can- 

 not be united, but the extraction of a small portion is not ne- 

 cessarily fatal, as a fleshy cicatrix forms, and so makes good 

 the loss. We have already mentioned, in their respective 84 

 places, that the skull of the bear is the weakest of all, and 

 that of the parrot the hardest. 



CHAP. 49. THE BRAIN. 



The brain exists in all animals which have blood, and in 

 those sea animals as well, which we have already mentioned 

 as mollusks, although they are destitute of blood, the poly- 

 pus, for instance. Man, however, has, in proportion to his 

 body, the most voluminous brain of all. This, too, is the 

 most humid, and the coldest of all the viscera, and is enve- 

 loped above and below with two membranous integuments, 

 for either of which to be broken is fatal. In addition to these 

 facts, we may remark that the brain is larger in men than in 



81 See B. v. c. 29. 



82 <Pa\aic()OKupaZ. See B. x. c. 68. 



83 He borrows this from Aristotle. 



84 B. viii. c. 54, and B. x. c. 58. The skull of the bear is not tbinner 

 or weaker than that of other animals of its own size ; but tbe skull of the 

 parrot, in proportion to those of other birds, is remarkably hard. 



