394 



THE RESPIRATION 



Nabarro). It is of course necessary in making these comparisons to 

 secure the coefficient of oxidation both when the tissue is at rest and 

 when it is thrown into varying degrees of activity. Special attention 

 has been devoted to the requirements of skeletal muscle, heart muscle 

 and the salivary glands. 



Skeletal Muscle. In observations on skeletal muscle, Verzar (cf. 27) 

 isolated the gastrocnemius muscle of the cat, and without disturbing its 

 blood supply collected samples of blood by introducing a 1 c.c. pipette 

 into a branch of the saphenous vein. Activity was produced by throw- 

 ing the muscle into tetanus by the application of an electrical stimulus 

 to the sciatic nerve. During its contraction the muscle lifted a weight, 

 so that it did about 70 gram-centimeters of work at the beginning of 

 each period of tetanus. The velocity of bloodflow was determined by 

 the rate at which the blood flowed along the pipette, and the 2 consump- 

 tion, by the difference in percentage of 2 in the venous and the arterial 

 blood. These measurements were made: (1) before contraction, (2) dur- 

 ing contraction, and (3) after contraction. It was found that during the 

 tetanus the 2 consumption in some cases was greater than during rest, 

 while in others it was actually less,, but in eveiy instance a great increase 

 in 2 consumption followed the tetanus that is, the call for 2 continues 

 for some time after the actual work lias been performed. This result 



