212 ON GENERATION. 



variable quantity (for it is more abundant at the blunt end, 

 less so at the sharp end, and still less so in the other parts of 

 the egg), covering and surrounding the yelk on every side." 



In the hen's egg, however, I have observed that there are 

 not only differences in the albumen, but two albumens, each 

 surrounded with its proper membrane. One of these is thinner, 

 more liquid, and almost of the same consistence as that humour 

 which, remaining among the folds of the uterus, we have called 

 the matter and nourishment of the albumen; the other is 

 thicker, more viscid, and rather whiter in its colour, and in old 

 and stale eggs, and those that have been sat upon for some 

 days, it is of a yellowish cast. As this second albumen every- 

 where surrounds the yelk, so is it, in like manner, itself sur- 

 rounded by the more external fluid. That these two albumens 

 are distinct appears from this, that if after having removed the 

 shell you pierce the two outermost membranes, you will per- 

 ceive the external albuminous liquid to make its escape, and the 

 membranes to become collapsed and to sink down in the dish ; 

 the internal and thicker albumen, however, all the while retains 

 its place and globular figure, inasmuch as it is bounded by its 

 proper membrane, although this is of such tenuity that it 

 entirely escapes detection by the eye ; but if you then prick it, 

 the second albumen will forthwith begin to flow out, and the 

 mass will lose its globular shape; just as the water contained in 

 a bladder escapes when it is punctured; in like manner the 

 proper investing membrane of the vitellus being punctured, the 

 yellow fluid of which it consists escapes, and the original globular 

 form is destroyed. 



" The vitellus," says Fabricius, 1 " is so called from the word 

 vita, because the chick lives upon it; from its colour it is also 

 spoken of as the yellow of the egg, having been called by the 

 Greeks generally, ^pvaov, by Hippocrates yrXwpov, and by 

 Aristotle w/poy and Ae/eu0ov ; the ancients, such as Suidas in 

 Menander, called it VEOTTOV, i. e. the chick, because they believed 

 the chick to be engendered from this part. It is the smoothest 

 portion of the egg, and is contained within a most delicate 

 membrane, immediately escaping if this be torn, and losing all 

 figure ; it is sustained in the middle of the egg; and in one egg 



1 Op. cit. p. 23. 



