ANNITEESAET ADDKESS. xlvii 



The reverse is to be hoped ; nay, it may not be impossible to in- 

 dicate the source whence help will come. 



In commencing these remarks, mention was made of the great 

 obhgations under which the naturalist lies to the geologist and 

 palaeontologist. Assuredly the time will come when these obliga- 

 tions will be repaid tenfold, and when the maze of the world's past 

 history, through which the pure geologist and the pure palaeonto- 

 logist find no guidance, will be securely threaded by the clue fur- 

 nished 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. Eut he must be a half-hearted philo- 

 sopher who, believing in that possibility, and having watched the 

 gigantic strides of the biological sciences during the last twenty 

 years, doubts that science ^vdll 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 distinctly before the 

 minds of geologists for the last thirty years ; and if, at the present 

 time, it has seemed desirable to give them more definite and syste- 

 matic expression, it is because palaeontology is every day assuming 

 a greater importance, and now requires to rest on a basis whose 

 firmness is thoroughly well assured. Among its fundamental con- 

 ceptions, there must be no confusion between what is certain and 

 what is more or less probable*. But, pending the construction of 

 a surer foundation than palaeontology now possesses, it may be in- 

 Btructivc, assuming for the nonce the general correctness of the 

 ordinary hypothesis of geological contemporaneity, to consider 

 whether the deductions which are ordinarily drawn from the whole 

 body of palaeontological facts are justifiable. 



The e\'idence or which such conclusions are based is of two 

 kinds, negative and positive. The value of negative evidence, in 

 connexion with this inquiry, has been so fuUy and clearly discussed 



* " Le plus grand service qu'on puisse rendre i la science est d'y faire place 

 nette avant d'y rien couetruire." — Cuvier, 



