230 ON GENERATION. 



brane that bounds the empty space, so that the yelk now appears 

 to be connected with the cavity by means of the cicatricula; and 

 in the same measure as the yelk rises does the thicker portion 

 of the albumen sink into the sharp or lower end of the egg. 

 Whence it appears, as Fabricius rightly remarks, that Aristotle 1 

 was either in error, or that there is a mistake in the codex, 

 when it is said, " In this time" (viz., between three and four 

 days, and as many nights,) the yelk is brought to the summit, 

 Avhere the commencement of the egg is, and the egg is exposed 

 in this part," i. e. under the enlarged empty space. Now Aris- 

 totle 2 calls the principium ovi, or commencement of the egg, its 

 smaller end, which is last extruded. But it is certain that the 

 yelk ascends towards the blunt end of the egg, and that the 

 cavity there enlarges. And Aldrovandus is undoubtedly in 

 error when he speaks as if he had experience of the fact, and 

 says that the yelk rises to the sharp end. I will confess, never- 

 theless, that on the second or third day I have occasionally 

 observed the cicatricula expanded and the beginning of the 

 chick already laid, the yelk not having yet risen ; this, how- 

 ever, happens rarely, and I am inclined to ascribe it to some 

 weakness in the egg. 



On the second day of the incubation, or first day of inspec- 

 tion, the cicatricula in question is found to have enlarged to 

 the dimensions of a pea or lentil, and is divided into circles, 

 such as might be drawn with a pair of compasses, having an 

 extremely minute point for their centre. It is very probable 

 that Aldrovandus observed this spot, for he says : " In the 

 midst of the yellow a certain whitish something makes its ap- 

 pearance, which was not noticed by Aristotle " and also by 

 Goiter, when he expresses himself thus : " On the second day 

 there is in the middle of the yelk a part whiter than the rest;" 

 Parisanus, too, may have seen it ; he observes : " In the course 

 of the second day I observe a white body of the size and form 

 of a middling lentil ; and this is the semen of the cock covered 

 over with a white and most delicate tunic, which underlies the 

 two common membranes of the entire egg, but overlies the 

 tunica propria of the yelk." I believe, however, that no one 

 has yet said that this cicatricula occurs in every egg, or has 

 acknowledged it to be the origin of the chick. 



1 Hist. Anim. lib. vi, cap. 3. a Ibid. lib. iii, cap. 2. 



