DISCUSSION OF CERTAIN QUESTIONS RAISED BY 



PARKER IN A REVIEW OF " LIGHT AND THE 



BEHAVIOR OF ORGANISMS " 



S. O. MAST 

 Tlve Johns Hopkins University 



In this journal, Vol. i, pp. 461-464, there appeared a review 

 by G. H. Parker of the book entitled " Light and the Behavior 

 of Organisms." Certain statements in this review seem to 

 indicate that the position of the author of the book, the present 

 writer, was not grasped, other statements show clearly that the 

 author of the review takes exception to the interpretation of 

 various phenomena as described by the author of the book. 

 The questions at issue may be conveniently taken up seriatim. 



1. Parker says, p. 461, "The facts, new and old, are mar- 

 shalled with great consistency and uniformity in support of 

 Jennings's well-known views on animal orientation, and this 

 method of presentation is often so vigorously pursued as to 

 give the reader the impression of special pleading rather than 

 sound judgment. Many of the cases chosen to illustrate the 

 ' trial and error ' method of orientation must strike the impartial 

 reader as equally good examples for the support of the ' tropism ' 

 theory." I do not understand how my reviewer came to the 

 conclusion that cases were chosen to illustrate the " trial and 

 error theory " or any other theory of orientation. I reviewed 

 practically all previous work on orientation and thoroughly in- 

 vestigated the subject myself, studying the process in repre- 

 sentative species of plants and of all of the different classes of 

 animals. The methods of orientation in all are described in 

 detail regardless of what theories they fit. Judging from Parker's 

 statement one might conclude that all had been discarded except 

 those which fit preconceived notions. Whether or not " sound 

 judgment " was exercised in dealing with the subjects treated 

 is a question which I shall leave in the hands of my readers. 



2. Parker implies repeatedly in his review that the methods 

 of orientation as described in my book support " the tropism 

 theory." But unfortunately he fails to state which one of the 

 fifteen 1 different tropism theories presented in my book, pp. 



1 There are now seventeen, two new ones having recently appeared. 



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