AIM, CONTENT, AND POINT OF VIEW 17 



work that go by the name ecological, which may or 

 may not be, and so many also which are truly ecologi- 

 cal but which do not pass under that name, that it is 

 necessary that the student shall be able to see through 

 its diverse guises and recognize its essential character. 

 Whenever the question arises as to the ecological 

 character of a fact, inference, or conclusion, its 

 ecological validity may be tested in the following 

 way: 



Do the facts, inferences, or conclusions show a 

 response to the inorganic or organic environment : 



1. As an individual of a species or kind of animal ? 



2. As a group of taxonomically related animals ? 



3. As an association of interacting animals ? 



REFERENCES ON THE ECOLOGICAL STANDPOINT 



In this I have listed only those papers which have seemed to 

 me particularly significant because of their point of view, regard- 

 less of whether or not they are primarily zoological or spe- 

 cifically mention ecology. 



BROOKS, W. K. 



1899. The Foundations of Zoology, pp. 339. New York. 

 Introductory, pp. 1-29 ; Huxley, and the Problem of 

 the Naturalist, pp. 33-46; Nature and Nurture, 

 pp. 49-79. 



1906. Heredity and Variation; Logical and Biological. 



Proc. Amer. Phil. Soc., Vol. XLV, pp. 70-76. 

 An extremely suggestive paper which should be read 



by every ecological student. 

 GANONG, W. F. 



1907. The Organization of the Ecological Investigation of the 



Physiological Life-Histories of Plants. Bot. Gaz., 

 Vol. XLIII, pp. 341-344. 

 c 



