ON GENERATION. 401 



which at length emerge flies or butterflies of the several 

 respects in which these differ in their mode of generation from 

 an egg, from what we have found in the hen's egg, will be 

 matter for remark in the proper place. 



Although all eggs consisting of yelk and white are not pro- 

 duced and fecundated in the same manner, but some are made 

 prolific through the intercourse of male and female, and 

 others in some other way (as of fishes) ; and although there is 

 some difference even in the mode in which eggs grow, some 

 attaining maturity within the body of the parent, others 

 continuing to be nourished and to grow when extruded, there 

 is still no reason why an embryo should not be developed in 

 the same precise manner in every egg always understood as 

 perfect as it is in the egg of the hen. Wherefore the his- 

 tory which has been given of the evolution of the chick from 

 the hen's egg may be regarded as applicable to the generation 

 of all other oviparous animals whatsoever, as well as to the 

 inferences or conclusions which may be deduced from thence. 



EXERCISE THE SIXTY-THIRD. 



Of the generation of viviparous animals. 



Thus far have we treated mainly of the generation of ovi- 

 parous animals ; we have still to speak particularly of the 

 other species of generation, the viviparous, to wit, in which 

 many things identical with those we have noticed in oviparous 

 generation will come to be observed. These we have reduced 

 into order, and here at length present for consideration. Even 

 the parts that appear paradoxical and in contradiction with 

 the current views of generation will, I believe, be found en- 

 tirely in conformity with truth. 



Among viviparous animals, man, the most perfect of all 

 creatures, occupies the foremost place; after him come our ordi- 

 nary domestic animals, of which some are soliped, such as the 

 horse and ass ; others bisulcate, as the ox, goat, sheep, deer, 

 and hog; others digitate, such as the dog, cat, rabbit, mouse, 

 and others of the same description ; from the modes of whose 



