president's addeess. 301 



the Darwinian theory, but that further thought and investiga- 

 tion have brought him to believe it incapable of accounting, ex- 

 cept as a subordinate agency, for the Origin of Species. The 

 object of his work is to set forth the difficulties which in the 

 author's belief are insuperable obstacles to the thorough accept- 

 ance of Darwin's theory, and to propose a new solution of the 

 problem. The solution is certainly, to me at least, a disappoint- 

 ment ; and Mr. Mivart himself seems to feel some misgiving as 

 to how far it really is a solution at all, for he specially depre- 

 cates the application to his work of the old French witticism 

 concerning opium, " Opium produces sleep by virtue of a certain 

 soporific quality which it possesses." Mr. Mivart's solution, 

 however, amounts simply to this : that new species arise by 

 virtue of a certain unexplained tendency to vary, which is pos- 

 sessed more or less by all creatures, which may, and probably 

 does, show itself in sudden leaps rather than in slow impalpable 

 modifications, and which is governed and modified by external 

 conditions and by forces inherent in the organisms themselves. 

 It will be seen that this does not put matters in a very clear 

 light, and though the solution may be true, it is not proved : 

 indeed Mr. Mivart does not attempt more than to show that it 

 is not contradicted by what we know of nature. Some of the 

 more important propositions which Mr. Mivart endeavours to 

 establish in support of his idea are as follows : — Variation occurs 

 suddenly, not by infinitesimal degrees ; And has definite limits ; 

 Mimicry is inexplicable on the theory of small initial variations ; 

 Closely similar structures in distantly related or non-related 

 animals are not intelligible on Darwin's theory ; Man's moral 

 development is similarly inexplicable. I shall not attempt to 

 adjudicate as to Mr. Mivart's success or failure ; that he has 

 shown good reasons for believing Natural Selection incompetent 

 by itself to the production of species as we now see them, must 

 I think be admitted : the probability of other forces sharing in 

 the work had, however, been already pointed out by the authors 

 of that theory. For myself, I laid down Mr. Mivart's book 

 feeling that it dealt with the case temperately and thoughtfully, 

 and was likely to be useful in bringing out certain difficulties 



