44° Animal Life and Intelligence. 



from natural selection and non-intelligent adaptation, I 

 see no a priori reason why any instinct, no matter how 

 complex, should not have had a like origin. 



Let us, however, next consider whether Professor Weis- 

 mann's theory of the origin of instincts necessarily 

 altogether excludes intelligence as a co-operating factor. 

 The essential point on which that theory is absolutely 

 insistent is that what is handed on through inheritance is 

 an innate, and not an individually acquired, character. Now, 

 since intelligent actions are characteristically individual, and 

 performed in special adaptation to special circumstances, 

 it would seem, at first sight, that the intelligent modification 

 of an instinct could not, on Professor Weismann's view, be 

 handed on. Let us consider whether this must be so. 



Speaking of ants and bees, Darwin pointed out that 

 their instincts could not possibly have been acquired by 

 inherited habit, since they are performed by neuter insects, 

 that is, by undeveloped females incapable of laying eggs 

 and continuing their race. For a habit to pass into an 

 instinct by inheritance, it is obviously necessary that the 

 organism which performs the habitual actions should be 

 capable of producing offspring by which these actions might 

 be inherited. But in this case the parental forms do not 

 possess these instincts, while the neuter insects which do 

 possess them are sterile. 



And how does Mr. Darwin meet this difficulty ? " It is 

 lessened, or, as I believe, disappears," he says,* " when it 

 is remembered that selection may be applied to the family 



are fertile sources of septicaemia and pyaemia — the pestilence and scourge so 

 much dreaded by operative surgeons." Now, if the leucocytes were separate 

 organisms, whose habits were being described, some might suppose that they 

 were actuated by intelligence, individual or inherited. But in this case the 

 activities are purely physiological. The marshalling of the cells during the 

 growth of tissue (e.g. the antler of a stag before described) is of like import. 

 And Dr. Verworn has shown that when a (presumably weak) electric current 

 is passed through a drop of water containing protozoa, they will, when the 

 current is closed, flock towards the negative pole, and when the current is 

 opened will travel towards the positive pole. The implication of all this is 

 that vital phenomena may be intensely purposive, and yet afford no evidence 

 or indication of the present or ancestral play of intelligence. 

 * " Origin of Species," p. 230. 



