ON GENERATION. 313 



EXERCISE THE FORTIETH. 



Of the hen. 



There are two instruments and two first causes of generation, 

 the male and the female for to the hen seems to belong the 

 formation of the egg, as to the cock the fertilizing principle. 

 In the act of intercourse, then, of these two, that which renders 

 the egg fruitful is either transmitted from the male to the female, 

 or by means of coition is generated in the hen. The nature of 

 this principle, however, is no less difficult to ascertain than are the 

 particulars of its communication, whether, for instance, we sup- 

 pose such communication to take place with the whole system 

 of the hen, or simply with her womb, or with the egg already 

 formed, or further, with all the eggs now commencing and 

 hereafter about to commence their existence in the ovary. For 

 it is probable, from what I have formerly mentioned, and also 

 from the experiment of Fabricius, 1 that but a few acts of inter- 

 course, and the consorting of the hen with the cock for some 

 days, are sufficient to fecundate her, or at least her womb, 

 during the whole year. And so far I can myself affirm, from 

 my own observation, to wit, that the twentieth egg laid by a 

 hen, after separation from the cock, has proved prolific. So 

 that, in like manner as it is well known that, from the seed of 

 male fishes shed into the water, a large mass of ova is impreg- 

 nated, and that in dogs, pigs, and other animals, a small number 

 of acts of intercourse suffice for the procreation of many young 

 ones, (some even think it well established, that if a bitch have 

 connexion more than three or four times, her fruitfulness is 

 impaired, and that more females than males are then engen- 

 dered), so may the cock, by a few treadings, render prolific not 

 only the egg in the womb, but also the whole ovarium, and, as 

 has been often said, the hen herself. Nay, what is more re- 

 markable, and indeed wonderful, it is said that in Persia, 2 on 

 cutting open the female mouse, the young ones still contained 

 in the belly are already pregnant ; in other words, they are 



1 Op. cit. p. 31 . 2 Arist. Hist. Anim. lib. vi, c. 37. 



