150 ANIMAL INSTINCTS. 



selves, and in their connexion with the whole physiology 

 of animal life. That which first offers itself is the 

 relation of physical structure to the existence and 

 variations of instincts a question closely pressed upon 

 us by recent doctrines and researches. Are the organic 

 forms or material apparatus to which particular in- 

 stincts are attached brought into this connexion by 

 special acts of creation? Or do changes gradually 

 going on, from whatever cause, in the forms and organs 

 of animals produce corresponding developments of the 

 instincts appropriate to each ? This question, which is 

 at once seen as deeply concerned with that of the Origin 

 of Species, goes straight to the point, and admits of no 

 evasion. Those who hold the doctrine of transmuta- 

 tion of species, and their derivation in the totality from 

 some few primitive forms, must needs acquiesce in the 

 latter view ; one sanctioned doubtless by the many cases 

 where change in external conditions creates new habits 

 of life, which by repetition and propagation take the 

 character of hereditary instincts, and modify to a certain 

 extent the bodily organisation. But the admission here 

 is a limited one only. The doctrine in question dis- 

 puted, indeed, but powerfully advocated involves 

 really the dependence of instinctive action upon organ^- 

 isation, under the direct relation of cause and effect 

 In assuming the evolution of new organic forms from 

 material causes acting on prior organisms, themselves 

 similarly developed from antecedent structures, instincts 

 come in only as sequent on such changes an ac- 

 quired and not an original possession. 



It will be seen, then, how much of the point of the 



