ON GENERATION. 231 



Meantime the chalazse or treadles will be seen to decline 

 from either end of the egg towards its sides, this being occa- 

 sioned by that alteration which we have noticed in the relative 

 situations of the two fluids. The treadle from the blunt end 

 descends somewhat ; the one from the sharp end rises in the 

 same proportion: as in a globe whose axis is set obliquely, one 

 pole is as much depressed below the horizon as the other is 

 raised above it. 



The vitellus, too, particularly in the situation of the cica- 

 tricula, begins to grow a little more diffluent than it was, and 

 raises its tunica propria, (which we have found in stale eggs 

 before incubation to be somewhat lax and wrinkled,) into a 

 tumour ; and it now appears to have recovered the same colour, 

 consistency, and sweetness of taste that it had in the egg just 

 laid. 



Such is the process in the course of the first day that leads 

 to the production of a new being, such the earliest trace of the 

 future chick. Aldrovandus adds : " the albumen suffers no 

 change," which is correct; but when he asserts that " the semen 

 of the cock can be seen in it," he as manifestly errs. Resting 

 on a most insufficient reason, he thought that the chalazse were 

 the semen of the cock, " because," forsooth, " the eggs that are 

 without chalazse are unfruitful." This I can very well believe ; 

 for these were then no proper eggs ; for all eggs, wind eggs as 

 well as those that are prolific, have chalazse. But he, misled 

 perhaps by the country women, who in Italian call the chalazse 

 galladura, fell into the vulgar error. Nor is Hieronymus 

 Fabricius guilty of a less grave mistake when he exhibits the 

 formation of the chick in a series of engravings, and contends 

 that it is produced from the chalazse ; overlooking the fact that 

 the chalazse are present the whole of the time, and unchanged, 

 though they have shifted their places; and that the commence- 

 ment of the chick is to be sought for at a distance from them. 



