RETINAL REFLEXES OF NARCOTIZED ANIMALS. 



immersion. After 14 minutes the animal was motionless and had 

 ceased to respond even to direct touch. On removal to fresh sea- 

 water it slowly recovered. During this period " darkness " fre- 

 quently seemed to produce a hackward and upward movement four 

 or five times the length of the fish. This immediately ceased on 

 switching on the light, the animal sinking. 



tb. Vcrtcbrata. Amphibia. Ranapipicns. The results of Cam- 

 eron and Sedziak for the frog under the action of benzene and 

 phenol have already been quoted. In order to complete this rec- 

 ord, the following experiments were carried out at the University 

 of Manitoba : 



Camphor (commercial preparation) was tested in two ways, 

 (a) 0.5 c.c. of a 20 per cent, solution in absolute alcohol was in- 

 jected into the anterior lymph sac of a frog weighing 60 grams. 

 There resulted gradual onset of paralysis, the respiratory move- 

 ments being the last retained. The animal died in about one and 

 one half hours. Change of illumination produced no effect at any 

 period. Since the immediate result of contact of the solution with 

 body fluid is precipitation of finely divided camphor, with subse- 

 quent slow solution, no certain dosage in this experiment could be 

 attempted. In a second frog injected with a smaller dose paralysis 

 intervened sooner, and again no " light " and " darkness " effects 

 could be elicited, (b) Two frogs were immersed in water sat- 

 urated with camphor. There was a much slower onset of paraly- 

 sis. One was almost completely paralyzed in three hours, the 

 second slightly affected. On removal from water breathing re- 

 commenced, but the animals subsequently died. There was no 

 evidence of reaction to light changes at any period. 



DISCUSSION OF RESULTS. 



It is evident that the response of animals under a certain type of 

 narcosis to illumination changes is widespread throughout marine 

 species ; this is probably true for land animals also. Our observa- 

 tions have been limited to species in which definite responses could 

 easily be detected. More detailed study would probably reveal 

 minuter changes, which, if employed, would show that the phenom- 

 enon is even more general. It is probable also that in certain cases 



