ACQUIRED CHARACTERS xliii 



the people who are competent to judge of the correct use of 

 deduction in difficult biological inquiries. It is not enough 

 to invent a hypothesis, which covers the facts, and then 

 regard it as true without farther study. In the present case 

 the facts are covered by at least three different and mutually- 

 exclusive hypotheses, special creation, inheritance of acquired 

 characters and natural selection. The d, priori method 

 breaks down hopelessly, and we must resort to the d posteriori 

 method. 



Now, no one has ever seen or heard of a genuine instance 

 of special creation. The doctrine of creation is a pure inven- 

 tion, fabricated to explain the facts. I think it could very 

 easily be proved that as a matter of fact it does not afford 

 the least glimmerings of an explanation of any of the facts ; 

 but that is by the way. It implies a disruption in nature ; 

 it is directly and immediately opposed to everything that 

 we know of natural phenomena ; it has deservedly fallen 

 to the last degree of discredit among aU who have the slightest 

 knowledge of the subject. Special creation may be left out 

 of account, because it is an unknown factor in natural events. 



Inheritance of acquired characters is a hypothesis that 

 may be dealt with on the same lines. Many are the attacks 

 which have been levelled against the theory that acquired 

 characters can be inherited. One of the most famous is 

 that of Weismaim, with his theory of the continuity of the 

 germ-plasm. The germinal material, or germ-plasm, he 

 said, is totally separate and cut off from the body-material 

 or soma-plasm. Hence, he argued, modifications of the 

 soma during life cannot by any possible means affect the 

 germ-plasm : there can be no use-inheritance, because there 

 is no way in the organism by which it could be accompKshed. 



This again is a pure deduction : and a dangerous one. 

 It does not follow in biology that because we cannot see 

 how a thing works, therefore it cannot work. Some physio- 

 logists indeed do think they see how the soma-plasm may 

 specifically affect the germ-plasm. But while we remain 

 in oui present ignorance as to the causes of development. 



