190 THE SUCCESSION OF ANIMAL FORMS 



evidence whatever as to identity of cause, and our reasoning 

 becomes at once the most transparent of fallacies. Further, we 

 have no right here to overlook the fact that the conditions of 

 the embryo are determined by those of a previous adult, and 

 that no sooner does this hereditary potentiality produce a new' 

 adult animal, than the terrible external agencies of the physical 

 world, in presence of which all life exists, begin to tell on the 

 organism, and after a struggle of longer or shorter duration it 

 succumbs to death, and its substance returns into inorganic 

 nature, a law from which even the longer life of the species 

 does not seem to exempt it. All this is so plain and manifest 

 that it is extraordinary that evolutionists will continue to use 

 such partial and imperfect arguments. Another illustration 

 may be taken from that application of the doctrine of natural 

 selection to explain the introduction of species in geological 

 time, which is so elaborately discussed by Sir C. Lyell in the 

 last edition of his " Principles of Geology." The great geolo- 

 gist evidently leans strongly to the theory, and claims for it the 

 " highest degree of probability," yet he perceives that there is 

 a serious gap in it ; since no modern fact has ever proved the 

 origin of a new species by modification. Such a gap, if it 

 existed in those grand analogies by which he explained geo- 

 logical formations through modern causes, would be admitted 

 to be fatal. 



A third illustration of the partial character of these hypo- 

 theses may be taken from the use made of the theory deduced 

 from modern physical discoveries, that life must be merely a 

 product of the continuous operation of physical laws. The 

 assumption — for it is nothing more — that the phenomena of life 

 are produced merely by some arrangement of physical forces, 

 even if it be admitted to be true, gives only a partial explana- 

 tion of the possible origin of life. It does not account for the 

 fact that hfe, as a force, or combination of forces, is set in 

 antagonism to all other forces. It does not account for the 



