HEREDITY AND EVOLUTION. 5 2 3 



we are used to be led from the known to the unknown, from the half- 

 perceived to the proven, the expectation of one year becoming the cer- 

 tainty of the next. It will aid appreciation of the change coming over 

 evolutionary science if it be realized that the new knowledge of hered- 

 ity and variation rather replaces than extends current ideas on those 

 subjects. 



Convention requires that a president should declare all well in his 

 science; but I can not think it a symptom indicative of much health 

 in our body that the task of assimilating the new knowledge has proved 

 so difficult. An eminent foreign professor lately told me that he be- 

 lieved there were not half a dozen in his country conversant with what 

 may be called Mendelism, though he added hopefully, ' I find these 

 things interest my students more than my colleagues.' A professed 

 biologist can not afford to ignore a new life history, the Okapi, or the 

 other last new version of the old story; but phenomena which put new 

 interpretations on the whole, facts witnessed continually by all who 

 are working in these fields, he may conveniently disregard as matters 

 of opinion. Had a discovery comparable in magnitude with that of 

 Mendel been announced in physics or in chemistry, it would at once 

 have been repeated and extended in every great scientific school 

 throughout the world. We could come to a British Association audi- 

 ence to discuss the details of our subject — the polymorphism of ex- 

 tracted types, the physiological meaning of segregation, its applica- 

 bility to the case of sex, the nature of non-segregable characters, and 

 like problems with which we are now dealing — sure of finding sound 

 and helpful criticism, nor would it be necessary on each occasion to 

 begin with a popular presentation of the rudiments. This state of 

 things in a progressive science has arisen, as I think, from a loss of 

 touch with the main line of inquiry. The successes of descriptive 

 zoology are so palpable and so attractive, that, not unnaturally, these 

 which are the means of progress have been mistaken for the end. But 

 now that the survey of terrestrial types by existing methods is happily 

 approaching completion, we may hope that our science will return to 

 its proper task, the detection of the fundamental nature of living 

 things. I say return, because, in spite of that perfecting of the instru- 

 ments of research characteristic of our time, and an extension of the 

 area of scrutiny, the last generation was nearer the main quest. No 

 one can study the history of biology without perceiving that in some 

 essential respects the spirit of the naturalists of fifty years ago was 

 truer in aim, and that their methods of inquiry were more direct and 

 more fertile — so far, at least, as the problem of evolution is concerned 

 — than those which have replaced them. 



If we study the researches begun by Kolreuter and continued with 

 great vigor till the middle of the sixties, we can not fail to see that, 

 had the experiments he and' his successors undertook been continued 



