370 THE DEVELOPMEJST HYPOTHESIS. 



differs so greatly that no visible resemblance of any kind 

 can be pointed out between them. Yet is the one changed 

 in the course of a few years into the other : changed so 

 gradually, that at no moment can it be said — Xow the 

 Beed ceases to be, and the tree exists. What can be more 

 widely contrasted than a newly-born child and the small, 

 semi-transparent, gelatinous spherule constituting the hu- 

 man ovum ? The infant is so complex in structure that a 

 cyclopaedia is needed to describe its constituent parts. 

 The germinal vesicle is so simple that it may be defined in 

 a line. Nevertheless, a few months suffice to develop the 

 one out of the other ; and that, too, by a series of modifi- 

 cations so small, that were the embryo examined at succes- 

 sive minutes, even a microscope would with difficulty dis- 

 close any sensible changes. That the uneducated and the 

 ill-educated should think the hypothesis that all races of 

 beings, man inclusive, may in process of time have been 

 evolved from the simj^lest monad, a ludicrous one, is not to 

 be wondered at. But for the physiologist, who knows that 

 every individual being is so evolved — who knows further, 

 that in their earliest condition the germs of all plants and 

 animals whatever are so similar, "that there is no apprecia- 

 ble distinction amongst them which would enable it to be 

 determined whether a particular molecule is the germ of a 

 conferva or of an oak, of a zoophyte or of a man ; " ^ — for 

 him to make a difficulty of the matter is inexcusable. Sure- 

 ly if a single cell may, when subjected to certain influences, 

 become a man in the space of twenty years ; there is 

 nothing absurd in the hypothesis that under certain other 

 influences, a cell may in the course of millions of years 

 give origin to the human race. The two processes are 

 generically the same; and difier only. in length and com- 

 plexity. 



We have, indeed, in the part taken by many scientific 

 * Carpenter. 



