PRESIDENTIAL ADDRESS. 23 



to embrace both of the great agencies of organic transforma- 

 tion, the functional and the selective. 



It is hardl}^ necessary to add that pure Lamarckism has 

 nothing whatever to do with such a question as whether acci- 

 dental modifications produced upon an organism, such as mu- 

 tilations from whatever cause, are inheritable, since these are 

 not due to continuous interaction between organism and envi- 

 ronment, are not the objects of the creature's efforts, and are 

 not acquired by any functional or habitual activities. And yet it 

 is no exaggeration to say that at least one-half, probabl}' much 

 more, of the space devoted by the Neo-Darwinians to the sup- 

 posed refutation of Lamarckism has been directed to proving 

 that acccidental mutilations are not transmitted to offspring. 



I do not deny that there is a doctrine of the transmissi- 

 bility of mutilations, and Darwin and others have collected a 

 large body of facts pointing strongly in that direction, while 

 Brown-Sequard is believed by many to have demonstrated 

 that hereditary epilepsy may be artificially superinduced in 

 guinea-pigs by lesions of the brain. And it may be that 

 Lamarck, coming upon similar facts, gave them a certain cre- 

 dence, but, as we have seen from typical passages quoted from 

 his work, these cases are not capable of being used in support 

 of his general philosophy, which rests entirely upon the 

 effects of functional activities exerted in response to secular 

 alterations in the surrounding conditions of existence. 



Whatever of truth, therefore, there may be in the doctrine 

 of the transmissibility of suddenl}^ or accidentally acquired 

 characters, it is clearly outside the present discussion and 

 need not be further touched upon. 



After the doctrine of natural selection had been clearly ex- 

 plained it was found to be so simple and at the same time so 

 far-reaching that it began to be questioned whether much that 



