70 CHARLES W. HARGITT 



there were some specimens light green, some darker green, 

 some very dark olivaceous. But it was not possible to dis- 

 tinguish that any significance attached to the nature of the 

 cage or receptacle, or that conditions of contact could have 

 played any role. 



In the next place experiments were made to test the part 

 played by the feet or toes as sensory agents. A specimen was 

 placed in a very dry jar lined with white blotting paper, after 

 having dried the animal very thoroughly with a dry towel. 

 Another was similarly treated and placed in a jar lined with 

 black blotting paper. These were put side by side on my table. 

 It was not possible to detect any effect whatsoever in the colora- 

 tion as a result after two hours' test. 



One of the specimens then had the toe disks clipped off with 

 sharp scissors and was placed by itself in a jar. This operation 

 very effectually inhibited the climbing power of the specimen, 

 but at no time was there the slightest evidence that it involved 

 any modification of the conditions affecting color. 



A still more heroic experiment was made along the same line, 

 viz., the section of the spinal cord after etherizing the specimen. 

 It was closely watched to see what effect the process of etheriza- 

 tion might have; but neither in the anesthesia, nor yet in the 

 actual section of the cord was it possible to detect any color 

 response. Later the entire cord was destroyed, but still without 

 effect on color. This experiment was repeated at another time, 

 but in a reverse order, viz., first a section of the sciatic nerve, 

 later section of the cord, and finally the decapitation of the 

 frog; but as before with absolutely negative results. In this 

 case bits of skin from different regions of the body were placed 

 in a damp jar along with living specimens to note what effect 

 this might have as to the color of such detached bits. It was 

 not possible to detect any certain evidence of direct color change, 

 though after some hours, there was a deadening of the color 

 such as one nearly always observes on recently dead frogs. 



It must appear, therefore, more or less evident that these 

 results are somewhat in conflict with those referred to by Lister 

 and Biedermann. They seem likewise in conflict w T ith results 

 reported by Rogers ('06, p. 168), to the effect that section of 

 the optic nerves resulted in a marked darkening of the skin. 

 He found, however, that a color variety of the same species 



