RESPIRATION. 



weigh. Determine the CO 2 elimination for another period equal 

 to the first period in time. 



How does the CO 2 elimination of the second period compare 

 with that of the first? What is the difference in the respiratory 

 quotient ? 



Repeat these experiments, using a cold-blooded animal instead 

 of the mouse. The frog will serve as a type. The mouse is an 

 animal of high respiratory activity. The frog is an animal of low 

 respiratory activity. What is the reason for a higher rate of gas 

 exchange in the mouse than in the frog ? 



Study the nature of the respiratory movements hi the frog. How 

 do they differ in mechanism from those of mammalia? How is 

 respiration carried on in fishes and in gilled amphibia ? 



What points in common have these three orders of animals as 

 far as respiration is concerned ? What points of difference ? 



A fair idea of the function of the circulation in respiration may 

 be obtained from a study of the circulation through the gill of 

 Necturus. 



