REACTIONS OF CERTAIN MOIST FOREST MAMMALS. 1 97 



After a few hours' treatment the mouse in the dry air became 

 very active. Beginning at the end of 16 hours it was quiet again 

 for several hours and it then became active again. It would run 

 up and seize the outlet tube with its teeth holding on until shaken 

 loose. In a few minutes it would repeat the performance. 

 After 36 hours it was very weak and was in a comatose condition; 

 it died 5 hours later after 41 hour exposure. 



Three mice were treated with air of different rates of flow. 

 The rates in liters per minute were 13, 30.5, and 45, and the rates 

 of evaporation were .35 c.c., .7 c.c., 1.7 c.c. respectively. The 

 mouse in the 45-liter flow died after a 1 9-hour treatment. An- 

 other mouse was put in the same bottle and weighed accurately. 

 It died after a i6-hour treatment and lost 2.69 grams. The mice 

 died with symptoms similar to the salamanders and frogs from 

 dense woods, tested by Shelford ('13) but the time to death was 

 much longer because of the covering of hair; and they are not so 

 restricted to their habitat, as they are sometimes found living up 

 in trees where the rate of evaporation is much greater than on 



the ground. 



5. General Discussion. 



Whether the evaporation was increased by more rapid rate of 

 flow, by drying the air, or by raising the temperature the general 

 behavior and reactions of the mice were the same. As a rule 

 the mice did not orient as quickly in the dry air as they did to a 

 difference in the rate of flow, or under certain conditions a change 

 in temperature. But differences were far less in the case of mice 

 in temperature gradients than in the case of Shelford's animals; 

 where the evaporation was the same there was no difference. 

 The mouse was always stimulated in the dry air and showed 

 agitation by rapid turnings in the cage, yawning or by stretching 

 and lying flat on the bottom. Sometimes the mouse moved 

 about at random in the division of the cage representing the 

 highest evaporation. This was especially the case when the 

 ends were reversed after the completion of the experiment 

 (Experiments 12 and 15). The selection of the air of lower 

 evaporation was usually accomplished by the mouse moving 

 back and forth along the cage; each period spent in the higher 

 evaporation lowered the threshold of stimulation and finally 



