Vol. XXXI. July, igi6. No. I 



BIOLOGICAL BULLETIN 



THE RELATION OF THE BODY TEMPERATURE OF 



CERTAIN COLD-BLOODED ANIMALS TO THAT 



OF THEIR ENVIRONMENT. 



CHARLES G. ROGERS AND ELSIE M. LEWIS. 1 



In a former paper 2 the present writers cited statements from 

 the literature showing that it is rather generally assumed by 

 biologists that the temperatures of the so-called cold-blooded 

 animals approximate very closely the temperatures of their sur- 

 rounding media, so closely, in fact, that the temperature of the 

 medium may be assumed to be the temperature of the animal in 

 question. It was also shown from citations to the original 

 experiments that such evidence as we have in regard to the 

 relation of the temperature of these cold-blooded animals to 

 that of their surroundings is to the effect that the temperature 

 of the animal is usually somewhat above that of the water in 

 which it is living. At that time we described experiments upon 

 the earthworm, Lumbricus agricola, which indicated that for 

 temperatures from 10 to 20 C. the temperature of the earth- 

 worm very closely approximated that of the water in which it 

 was immersed, often being the same. 



The brief review of the literature made at that time indicated 

 a lack of uniformity in results hardly believable. A more careful 

 survey of the available papers upon the subject of temperature 

 determinations in living animals convinced us of the advisability 

 of undertaking an experimental study of temperature relations 

 in a series of forms, making use of a uniform method which should 

 be accurate to a degree not attained in any of the previous studies. 

 The present report embodies results obtained in an effort to carry 



1 From the Department of Zoology, Oberlin College. 



2 Rogers, Charles G., and Lewis, Elsie M., "The Relation of the Body Tempera- 

 tures of the Earthworm to that of its Environment," BIOLOGICAL BULLETIN, 

 Vol. XXVII., No. 5, 1914. 



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