3l8 O. F. COOK 



tions are still lacking. The principles of evolution are being 

 sought in rare and exceptional phenomena while the apples con- 

 tinue to fall unregarded. Many evolutionary experiments have 

 been proposed which would require extensive and costly facili- 

 ties to be maintained for very long periods of time. Such sug- 

 gestions may not be carried out, but they have a present interest 

 as showing that current theories of descent do not apply in 

 nature at large, where the evolutionary possibilities of organ- 

 isms have been tested continuously for millions of years, and 

 the results are open freely for our inspection. 



The question turns on general biological interpretations and 

 standpoints far more than on formal proofs and demonstrations, 

 either sj^llogistic or statistical. The history of biology shows 

 what diverse and contradictory theories can be proved, or at 

 least rendered plausible, if their authors are allowed to select 

 the facts to go with them. 



A general law of organic succession must accommodate all 

 the pertinent facts. Each biologist can test it with the data of 

 his own experience if he have imagination enough to assume, 

 for the time being, the required standpoint. Indeed, one might 

 formulate procedure in such matters by saying that the more 

 general the law the less susceptible it is of being established by 

 reference to any small group of facts. Such reasoning from cir- 

 cumscribed data has always to be bolstered up by the argument, 

 expressed or implied, that the facts must mean what is alleged 

 because they cannot mean an3'thing else, a formula which trans- 

 mutes our ignorance into knowledge, by sheer intellectual al- 

 chemy. We unconsciously admit the author's unconscious 

 assumption that his standpoint is correct and final, and instead 

 of testing it by our own facts we accept his at their face value, 

 though every one of them may beg the question it is supposed 

 to answer. 



Ae long as experiments are limited to conditions of inbreed- 

 ing by which the desired phenomena can be induced, there will 

 be no lack of evidence for mutations and Mendelism. But even 

 if all the animals and plants were successively domesticated, 

 inbred and conventionalized into " character units," we would 

 still be as far as ever from having ascertained that these are the 



