588 



SCIENCE 



[Vol. LVI, No. 1456. 



animals under natural conditions. Perhaps 

 some day students of animal ibehavior from tlie 

 modern view-point will adequately work this 

 body of ore. It will not be an easy, nor a 

 completely profitable task. The trouble of 

 course is that, generally speaking, the naturalist 

 of the old school was not analytical, but rather 

 anecdotal, in his interest in the behavior and 

 habits of animals. 



It was just this -difference that marked of£ 

 the new school of animal behavior from the old. 

 If what living things do is the most important 

 consideration in distinguishing them from non- 

 living things, it would seem clear that our 

 knowledge of biology in general is bound to be 

 increased if we apply to the study of what they 

 do such precise analytical experimental meth- 

 ods as will give definite knowledge of at least 

 some of the variables concerned in the determi- 

 nation of why they do it. In short, instead of 

 intei'iJreting what animals do in terms of a 

 crude anthropopsyehism why not be objective, 

 and ,by experimentally modifying and control- 

 ling the ainimal's behavior learn something of 

 the biological processes 'back of it? 



Around 1900 it was pretty unanimously 

 agreed that this was the thing to do, and it was 

 done. For a few years a glib familiarity with 

 "tropisms" and "reflex movements" was as es- 

 sential to biological respectability as a corre- 

 sponding acquaintance with "genes" and "cross- 

 ing-over" is now. Two schools of thought and 

 opinion crystallized, the one led by Loeb and 

 the other by Jennings. They may be charac- 

 terized, with perhaps the least chance of giving 

 offense to anybody, as respectively the more 

 simply mechanistic and the less simply mechan- 

 istic ways of regarding the happenings called 

 life. The two cohorts of followers fought and 

 bled on the battle-fields of "forced movements," 

 "trial and error," and so on, with the utmost 

 nobility and sacrifice of ink. 



Quite unfortunately, as it seems to me, this 

 fundamentally important line of research so 

 brilliantly inaugurated, began after a decade or 

 so to languish. Loeb turned off to physical 

 chemistry and Jennings to genetics, and with 

 the generals gone the armies melted away, to 

 ally themselves to what they supposed to be 



more auspicious, or at leasft moi'e fashionable 

 movements. The ease well illustrates the po- 

 tency of the sheepish elements in human be- 

 havior. For no informed person supposes for 

 a moment that all the problems of animal be- 

 ha\dor and comparative psychology have been 

 completely solved. Quite on the contrary the 

 field has just been well opened up. And it 

 is my conviction, based on some personal ex- 

 perience, that there is no other discipline which 

 gives the student such an insight and 'grasp 

 of fundamentals in the philosophj' of 'biology 

 as does the fii-st-hand study of animal behavior. 

 Every student in training for a career in any 

 field of biology will find it extremely valuable 

 in his future work to have done a piece of care- 

 ful work in animal behavior under competent 

 dii'ection and guidance. 



VII 



We come now to the consideration of what, 

 directly and in its numerous ramifications, is the 

 dominant mode dn present-day biology. I refer, 

 of coui'se, to exiserimental evolution. Begin- 

 ning philosop'hically as a reaction against the 

 sterility of pure morphology as a method of 

 solving the great problems of organic evolution, 

 it owes its 'actual origin as a major move- 

 ment in ibiological thought to two circum- 

 stances, first, the bringing to light of tlie long- 

 forgotten papers on the mode of inheritance 

 of characters in certain plants by the Austrian 

 monk, Gregor Mendel; and second, to the in- 

 auguration of the biometric method in biology 

 by Francis Galton, Karl Pearson, and W. F. 

 R. Weldon. It was plain enough to the writers 

 of the Neo-Darwinian 'school, as indeed to 

 everybody else who had grasped anything of 

 the meaning of Darwin's work, that the basic 

 factors in organic evolution were variation and 

 heredity. Why not, then, study these factors 

 directly, intensively, experimentally, and quan- 

 titatively? There could possiblj' be 'but one 

 sensible answer to this question. And because 

 this is so is the reason that genetics and bi- 

 ometry oame upon us with such a rush, and 

 'have grown and prospered so vigorously. 



Bateson, in the address to which I have al- 

 ready referred, tells the story of this change 



