INFLUENCE OF TEMPERATURE ON RANA AKKOLATA. 253 



river bank and snaps at passing flies" sustains. The change in 

 temperature of its blood causes its tissues to show a much more 

 intensive metabolism. Krogh in his numerous studies on the 

 influence of temperature on poikilothermous animals gave as his 

 opinion that the influence of temperature on the animal's metab- 

 olism is of double nature. On the one hand the basal metab- 

 olism is increased, on the other hand the tonus of the muscle is 

 increased and causes in that way an increased muscle metabolism. 

 The latter process is regulated by the central nervous system 

 and in fact he observed that in decerebrated animals the tem- 

 perature did not have as much influence on the CO 2 output as 

 in normal animals. Moreover Krogh is of the opinion that a reg- 

 ular decrease can be observed in the temperature coefficient. For 

 this reason I figured out the temperature coefficients of my own 

 experiments which are given in Table II. 



TABLE II. 



Range. Coeff. 



i-n 1.6 



11-21 1.56 



21-31 3-6 



Instead of a decrease we notice an increase. We must however 

 keep in mind that these experiments have been made on normal 

 animals. The quoted experiments of H. Schultze give the same 

 result. 



I do not dare to say in how far the rule of van't Hoff holds 

 true for this case. I believe that we can not be careful enough 

 in drawing conclusions on this point. The reactions of the 

 organism as a whole can not but with extreme care be compared 

 with simple chemical reactions. Not only the two factors 

 emphasized by Krogh play a role in the processes of which we 

 see the final result in our urinary analysis, but also the blood 

 pressure, the water intake which has been shown by Overton 11 

 to be very strongly influenced by temperature, and the function 

 of the kidneys. For this reason it seems not very probable that 

 the final result of all these processes should be comparable to a 



II E. Overton, " Neununddreiszig Thesen iiber die Wasserokonomie and die 

 osmotischen Eigenschaften der Amphibienhaut." Vorl. Mitt, filiysik. medizin. 

 Gesellsch., Wiirzbarg, N. F., 36, 282, 1904, 



