CHAPTER XV. 

 THE ORIGIN OF ORGANIC FORMS. 



THE account which it gives of the origin of 

 organic forms has gained for the Evolution 

 Hypothesis its widest acceptance. Here its advocates 

 put forth all their strength. They claim to have 

 established the doctrine in this department beyond 

 reasonable doubt. 



Surveying the realm of organized matter, we see 

 broad and deep lines differencing great classes of 

 instances ; and within these lines large groups clearly 

 distinguished by dividing limits limits never, within 

 the range of experience, obliterated ; and so, by suc- 

 cessive divisions, until we reach variations that char- 

 acterize, not the species, but the individual. This 

 vast multiformity, seen in the contrasts between the 

 two great kingdoms and in the incalculable diversities 

 found in either, is to be derived from one primordial 

 mode of living matter. Evolution is bound, not only 

 to show that out of the same original living matter 

 all these organisms may have sprung ; it is bound to 

 show that they must have sprung from it, and to show 

 how : it is bound to account for their present form by 

 setting out the law of a ceaseless onward movement 



