OLFACTORY REACTIONS IN AMPHIBIANS (331 



The on^ exception was Toad No. 4, which seemed to be in a 

 semi-hibernating condition during the entire period. Two other 

 toads taken in the fall of 1912 were likewise tested with this 

 apparatus. * Although no two individuals were identical, the 

 results of the trials agree in all essentials. 



Ji. Substances used in the tests 



Oil of cloves, oil of pennyroyal, oil of rose geranium, cedar 

 oil, bergamot oil, aniline oil, carbolic acid, olive oil, castor oil, 

 and cod liver oil were used, though some of the substances gave 

 entirely negative results. 



Trials were also made with the odor stream from food ma- 

 terials used by the toad. For these tests mealworm larvae, 

 earthworms, dungworms, and cockroaches and other insects 

 were put directly into the chamber, C and the air stream was 

 allowed to carry over any odors that were present. In no case 

 was there evidence of olfactory stimulation from these bodies. 



5. Experiments 



The attempt of Graber ('85) to determine the olfactory 

 reactions in some of the amphibians proved unsatisfactory. 

 Aronsohn ('86) and Gourewitsch ('83) noted the effect of odors 

 on the rate of respiration. The animals, while confined in covered 

 beakers, were exposed to odors of turpentine and eau de cologne 

 with disturbing results. 



Early in my own tests it was seen that chloroform, ammonia, 

 ether, turpentine, formol or alcohol when introduced into the 

 chamber were disturbing. Even though the air stream with these 

 substances was not near the nostril, reactions followed very 

 quickly and with the proximity of the stream to the nose the 

 disturbance was increased. 



Ammonia, chloroform and turpentine when directed upon 

 the anterior head region induced the toad to jump away from 

 the tube to one side or even out of the chamber. The odor of 

 turpentine resulted in a very characteristic attitude, the head 



