280 PRINCIPLES OF STOCK-BREEDING. 



the same class of facts in animals more highly organ- 

 ized. 1 



" It appears, from Mr. Newport's ingenious experi- 

 ments, that the contact of a single spermatozoon is 

 not adequate to produce complete fecundation, but 

 that the penetration of a certain number of sperma- 

 tozoa is requisite ; and he has ascertained that fecun- 

 dation may be effected partially (so as to occasion 

 some, though not all, of the normal changes in the 

 ovum) by a smaller amount." a 



The last-mentioned fact, it will be noticed, is in 

 accordance with the experience of breeders of fowls, 

 to which reference has already been made. 



1 " Cyclopaedia of Anatomy and Physiology," vol. ii., p. 464 ; Flint's 

 " Physiology of Man," vol. v., p. 353. 



* Carpenter's " Comparative Physiology," p. 532. 



