330 ON GENERATION. 



the similarity of its consistency to that of the chalazse. But 

 the red mass (which Fabricius regarded as the liver) is neither 

 situated in nor near the chalaza, but in the middle of the 

 clear colliquament ; and it is not any rudiment of the liver but 

 of the heart alone. Neither does his view square with the 

 example he quotes of the tadpole, " of which/' he says, " there 

 is nothing to be seen but the head and the tail, that is to say, 

 the head and spine, without a trace of upper or lower extremi- 

 ties." And he adds, " he who has seen a chalaza, and this 

 kind of conception, in so far as the body is concerned, will 

 believe that in the former, he has already seen the latter." I, 

 however, have frequently dissected the tadpole, and have found 

 the belly of large size, and containing intestines and liver 

 and heart pulsating ; I have also distinguished the head and 

 the eyes. The part which Fabricius takes for the head, is the 

 rounded mass [or entire body] of the tadpole, whence the 

 creature is called ' gyrinus/ from its circular form. It has a 

 tail with which it swims, but is without legs. About the 

 epoch of the summer solstice, it loses the tail, when the ex- 

 tremities begin to sprout. Nothing however occurs in the 

 nature of a division of the embryo pullet into the head and 

 spine, which should induce us to regard it as produced from 

 the chalazse, and in the same manner as the tadpole. 



The position and fame of Fabricius, however, a man exceed- 

 ingly well skilled in anatomy, do not allow me to push this 

 refutation farther. Nor indeed, is there any necessity so to 

 do, seeing that the thing is so clearly exhibited in our history. 



Our author concludes, by stating that his opinion is of 

 great antiquity, and was in vogue even in the times of Aristotle. 



For my own part, nevertheless, I regard the view of Ulysses 

 Aldrovandus as the older, he maintaining, that the chalazse are 

 the spermatic fluid of the cock, from which and through which 

 alike the chick is engendered. 



Neither notion, however, is founded on fact, but is the 

 popular error of all times : the chalazse, treads, or treadles, as 

 our English name implies, are still regarded by the country folks 

 as the semen of the cock. 



" The treadles (gran dines)," says Aldrovaudus; " are the 

 spermatic fluid of the cock, because no fertile egg is without 

 them." But neither is any unprolific egg without these parts, 



