Mat 1, 1908] 



SCIENCE 



701 



named the local action theory. I believe there 

 is no ground for misunderstanding the theory 

 that I was criticizing, though this seems to 

 have occurred in certain cases. 



My discussion has been attacked from two 

 sides. In one recent number of Science 

 Parker" takes the ground that the local action 

 theory is not held, so that it was not worth 

 while to demolish it; while in another recent 

 number, Torrey' expressly defends the local ac- 

 tion theory. These mutually destructive criti- 

 cisms naturally relieve me of some embarrass- 

 ment in replying to both. Torrey's elaborate 

 defense shows that the theory is still very 

 much alive and I can, therefore, only greet with 

 pleasure Parker's ready support of my main 

 contention, even though this takes the form of 

 Sairey Gamp's crushing retort, " Who deniges 

 of it, Betsey ? Who deniges of it ? " Parker's 

 work has been mainly with more complex ani- 

 mals than those dealt with in my book, and his 

 interests have lain rather in the field of sense 

 physiology than in the development of activity. 

 I can, therefore, readily understand that he 

 should find it inconceivable that such a view 

 should be held; he has doubtless not met it in 

 opposition at every turn, as have those working 

 with the lowest organisms, and as I now meet 

 it in Torrey's paper. In my book I have given 

 precise statements of the theory in the form 

 of quotations from authors of highest stand- 

 ing. Bohn' in his recent exposition adds 

 others. None of the authors quoted has, so 

 far as I am aware, repudiated the local action 

 theory. It would appear, therefore, that a 

 statement of the relation of the observed facts 

 to this theory was much needed. 



Before turning to the arguments urged in 

 support of the local action theory, another 

 criticism of my discussion, made or implied 

 by most of my critics, must be dealt with. 

 This may he put as follows. Suppose that the 

 simple, local action theory of tropisma is not 

 satisfactory. Nevertheless, there is another, 

 less precise, less simple, theory of tropisms 

 which is of itself important; a theory in sup- 



' Science, October 25, 1907. 



' Science, September 6, 1907 ("the response to 

 Stimulation is local," p. 319, etc.). 



' hoc. cit. 



port of which Parker and Torrey cite the 

 circus movements of animals when the sense 

 organs of one side have been obstructed. A 

 theory of such importance, it is contended, 

 should have been dealt with in a general work 

 on the behavior of the lower organisms. 

 Further, the chapter criticizing a theory under 

 the name of tropism gives the impression that 

 this other theory is also condemned, though 

 arguments against it are not advanced. 



To this criticism my book is justly open. I 

 should have given an exposition of the theory 

 in question, with an attempt to estimate the 

 part it plays in the behavior of the lower or- 

 ganisms. This unpurposed omission was 

 partly due to the fact that the two groups of 

 whose behavior I gave a detailed exposition — 

 the Protozoa and Ooelenterata — have furnished 

 practically none of the evidence cited by my 

 critics; partly to my attempt to focus atten- 

 tion upon the local action theory as of in- 

 finitely greater importance than the other form 

 of the theory. But even though I held that 

 action in accordance with the complex form of 

 the theory plays little part in the behavior of 

 the lower animals, the phenomena and theory 

 should have been set forth, and I regret that 

 this was not done. 



We may now return to the criticisms and 

 defense of the local action theory. Regarding 

 the nature of my criticisms, one point must 

 be emphasized — a point that has been much 

 misunderstood, though I believe I expressed 

 myself explicitly on the matter. I made no 

 attempt, and had no desire, to deny the exist- 

 ence of the factors on which the local action 

 theory, or any other existing theory of tro- 

 pisms, was based. So far as local action is 

 concerned, I emphasized in my book such cases 

 as were established, and gave a list of them on 

 page 306. The question which I tried to an- 

 swer in my discussion of tropisms could be put 

 thus : After some years of study of the be- 

 havior of the lower organisms, what is your 

 impression regarding the extent and impor- 

 tance of the part played by tropisms ? A well- 

 known investigator, after one of the most 

 thorough and detailed studies of the behavior 

 of a certain group of invertebrates that have 

 ever been made, in which he watched and ex- 



