Masterpieces of Science 



growths on the wild rose or oak tree. \ \ ;th all 

 organic beings, excepting perhaps some of the 

 very lowest, sexual reproduction seems to be 

 essentially similar. With all, as far as is at 

 present known, the germinal vesicle is the same; 

 so that all organisms start from a common origin. 

 If we look even to the two main divisions — ■ 

 namely, to the animal and vegetable kingdoms 

 — certain low forms are so far intermediate in 

 character that naturalists have disputed to which 

 kingdom they should be referred. As Professor 

 Asa Gray has remarked, "the spores and other 

 reproductive bodies of many of the lower algae 

 may claim to have first a characteristically 

 animal, and then an unequivocally vegetable 

 existence." Therefore, on the principle of nat- 

 tural selection with divergence of character, it 

 does not seem incredible that, from some such 

 low and intermediate form, both animals and 

 plants may have been developed; and, if we admit 

 this, we must likewise admit that all the organic 

 beings which have ever lived on this earth may be 

 descended from some one primordial form. But 

 this inference is chiefly grounded on analogy, and 

 it is immaterial whether or not it is accepted. 

 No doubt it is possible, as Mr. G. H. Lewes has 

 urged, that at the first commencement of life 

 many different forms were evolved; but if so, we 

 may conclude that only a very few have left 

 modified descendants. For, as I have recently 

 remarked in regard to the members of each great 

 kingdom, such as the Vertebrata, Articulata, etc., 

 26 



