54 JOSEPH HALL BODINE 



blackened. Both animals whose "eyes had and had not been pre- 

 viously blackened were used, but no differences in response were 

 noted. Table 1 and figure 1 show that a decrease in the rate of 

 CO2 output was always associated with decapitation. The degree 

 of this decrease varies slightly for different animals, and it is 

 usually lower than that for individuals with blackened eyes. 

 When decapitated, the amount of actual respiring tissue taken 

 off with the head is rather large and can account for much of the 

 decrease in rate below that for blackened-eyed individuals. The 



N A B C D 



Fig. 3 Curves showing the effect of blackening the eyes, shortly after the 

 operation, tAventy-four hours after, and the removal of the varnish after twenty- 

 four hours on the rate of CO2 output. Based on average of six individuals. 

 Solid lines for experimental animals. Broken lines for normal animals. Points 

 on abscissas, A^, normal animals at start; A, animals with eyes blackened — at 

 once; B, animals with eyes blackened — after twenty-four hours; C, animals from 

 whose eyes varnish was removed — after twenty-four hours; D, normal animals 

 after twenty-four hours. Ordinates same as in figure L For further description 

 see text. 



operation itself also doubtless exerts some effect. The combined 

 effects of these two factors undoubtedly account for much of 

 this decreased rate, and as a matter of fact it has been found 

 that when the head is put into the respiration tube with the 

 decapitated animal the decrease in the rate of CO2 output is 

 strikingly similar to that observed for blackened-eyed individuals. 

 The above results then show that decapitation results in a 

 marked decrease in rate of COo output not greatly different in 

 magnitude from that observed for blackened-eyed individuals. 



