630 JONATHAN RISSER 



the toads to the new conditions. Toads not accustomed to the 

 chamber were at first much disturbed, reacting to various other 

 influences. Attempts to crawl out of the chamber, to bite the 

 end of the tube, d, or to be restless within the chamber were 

 some of the reactions noted. After adjustment normal re- 

 actions were then exhibited, such as feeding or burrowing into 

 the soil. The apparatus was kept well ventilated between 

 periods of experimentation as well as during the testing periods. 



2. Rate of flow of odor-stream 



The rate of flow of the air stream was made as uniform as 

 possible. If allowed to flow uninterruptedly the 3000 cubic 

 centimeters of air in B were displaced by the water from A 

 in from 80 to 90 minutes. At this rate the flow is approximately 

 35 cubic centimeters per minute. That such a stream is not 

 sufficiently strong to be perceptible can be demonstrated by plac- 

 ing the nozzle tube near the moistened lips or the tongue. The 

 flow of the stream could also be judged from the frequency of 

 escaping bubbles when the end of the tube was immersed in 

 water. 



The tests as carried out followed a uniform plan consisting of, 

 first, a control test with air, and secondly, a trial proper with the 

 odor stream. 



3. Methods 



In the control test the toads were first subjected to the air 

 stream coming from B. The nozzle tube, d, was directed toward 

 various body regions, namely, flank, axillary region, anal region, 

 and surface of the eye (as near as possible without contact). 

 After this test for possible stimulation of integumentary sense 

 organs, the_ air stream was next directed to the nostril to ascer- 

 tain if there was any stimulation of the nasal epithelium. The 

 test with the odor stream followed next and the same parts of 

 the body were tested as before. 



The toads used in the feeding experiments were used for the 

 tests with the odor stream and were normal in all their activities. 



