214 LAY SERMONS, ADDRESSES, AND REVIEWS. [x 



the great obligations under which the naturalist lies to 

 the geologist and palaeontologist. Assuredly the time 

 will come when these obligations will be repaid tenfold, 

 and when the maze of the world's past history, through 

 which the pure geologist and the pure palaeontologist 

 find no guidance, will be securely threaded by the clue 

 furnished by the naturalist. 



All who are competent to express an opinion on the 

 subject are, at present, agreed that the manifold varieties 

 of animal and vegetable form have not either come into 

 existence by chance, nor result from capricious exertions 

 of creative power ; but that they have taken place in a 

 definite order, the statement of which order is what 

 men of science term a natural law. Whether such a 

 law is to be regarded as an expression of the mode of 

 operation of natural forces, or whether it is simply a 

 statement of the manner in which a supernatural power 

 has thought fit to act, is a secondary question, so long 

 as the existence of the law and the possibility of its 

 discovery by the human intellect are granted. But he 

 must be a half-hearted philosopher who, believing in 

 that possibility, and having watched the gigantic strides 

 of the biological sciences during the last twenty years, 

 doubts that science will sooner or later make this further 

 step, so as to become possessed of the law of evolution 

 of organic forms — of the unvarying order of that great 

 chain of causes and effects of which all organic forms, 

 ancient and modern, are the links. And then, if ever, 

 we shall be able to begin to discuss, with profit, the 

 questions respecting the commencement of life, and the 

 nature of the successive populations of the globe, which 

 so many seem to think are already answered. 



The preceding arguments make no particular claim to 

 novelty ; indeed they have been floating more or less 



