BODY TEMPERATURE OF CERTAIN COLD-BLOODED ANIMALS . 1 1 



the thermostat and near to the free junction. The wire made it 

 possible to remove the animal from the couple and to replace it 

 with a minimum of effort whenever it was necessary to make a 

 reading for the parasitic current in the system. The repeated 

 insertion of the junction seemed to cause no trouble whatever, 

 for the animals were just as lively after a long series of temperature 

 readings as before. It was easy by this way of handling to keep 

 several specimens in the thermostat at one time and to take 

 readings upon the whole series, in regular order, at the different 

 temperatures used. 



The method employed gave us no opportunity to investigate 

 the time required for an animal to adjust himself to the temper- 

 ature of his surroundings, though such information would be of 

 interest. From the very little information we have upon the 

 subject it seems likely that there is a definite mathematical re- 

 lation between the mass of the animal and the time required for 

 adjustment. The salamanders used were allowed from five to 

 ten minutes to become adjusted to their new conditions when 

 changed from one bath to another which was a few degrees dif- 

 ferent in temperature. This time is certainly in excess of the 

 minimum required. The salamanders proved to be the most 

 satisfactory of any of the forms studied on account of the ease of 

 manipulation, endurance, etc. 



Inspection of Table IV. will reveal the close approximation of 

 the temperature of these animals to that of their environment. 

 In most cases a difference of only a few thousandths or at most 

 of a few hundredths of a degree could be determined. Of the 

 28 specimens reported 12 showed the same temperature as that 

 of the water in which they were immersed, 10 showed an average 

 temperature 0.01293 below that of the w r ater, and 6 an average 

 temperature 0.01225 above that of the water. From the fact 

 that so many individuals show no variation of temperature at all 

 from that of the water in which they were immersed, and that the 

 deviations above and below the temperature of the water prac- 

 tically balance we believe it safe to say that these animals tend 

 to assume the temperature of the water in which they are living 

 to within a very few thousandths of a degree. It is entirely 

 possible that a longer watching of the temperatures of these 



