2o8 'Journal of Comparative Neurology and Psychology. 



experiment. None of these specimens showed any signs of 

 awakening for three hours, and probably they would have re- 

 mained quiet for a much longer time. 



THE EFFECT OF LIGHT ON THE DURATION OF THE DEATH FEINT. 



The duration of the death feint in Ranatra is diminished, as a 

 rule, by exposure to bright light. Twelve Ranatras were exposed 

 to the light of a sixteen candle-power electric light at an average 

 distance of about one foot. At the same time another lot of 

 thirteen specimens was exposed to a much dimmer light in another 

 part of the room. The duration ot the feints under thesecondi- 

 tions was as follows: 



Specimens Under Bright Light. 



Specimens Under Dim Light. 



14 



41 

 46 



70 



71 



<)3 



lOI 



174 



Average 75.8 minutes. 



H 

 33 

 41 

 6S 

 90 



105 



"S 

 139 



HS 

 180 

 210 



255 



Average 116 minutes. 



Ranatras are roused from their death feint much more quickly 

 if the light is moved about near them than if it is kept stationary. 

 In experimenting on the effects of moving light one lot of speci- 

 mens was placed under a sixteen candle-power lamp six inches 

 away, a flat dish of water being interposed to cut out the heat 

 rays. Another lot of specimens w^as exposed in the same way 

 except that the light was kept moving above them at an average 

 distance of about six inches. The duration of the death feints 

 under these conditions was as follows: 



