A STUDY OF COLOR VISION IN THE RING-DOVE 43 



students of behavior to discover the most efficient means of 

 developing preparatory habits in animals. 



In concluding this paper, the writer can not refrain from 

 calling attention to the waste of time which results from the 

 sacrificing of trained animals at the end of an investigation. 

 It should be possible, through exchange, to make the same 

 subject serve in various experiments. And different experi- 

 menters, supposing our methods to be reasonably standardized, 

 might study quite different problems on the basis of similar 

 preparatory habits. Thus, for example, the doves which in this 

 investigation have been trained to certain visual reactions, might 

 perfectly well be employed for other forms of visual response, 

 or even to greater advantage for studies of the relation of the 

 central nervous system to the acquired responses. It is sug- 

 gested, therefore, that American investigators who are actively 

 engaged in studies in animal behavior keep in close touch and 

 develop a system of reporting their experiments while in pro- 

 gress, which may serve as a basis for the serviceable exchange of 

 trained subjects. The writer happens to have on hand at the 

 moment of writing three tame crows which are highly trained 

 in certain modes of response. The labor of taming and training 

 them would have to be valued at several hundred dollars. It 

 is impossible, under present conditions, to make use of these 

 birds, and unless some other investigator can be found who 

 can take advantage of this preparation, they will have to be 

 either set at liberty or otherwise sacrificed. 



