The call for oxygen by muscle 



75 



The above figures leave no room for doubt that the quantity 

 of oxygen used increases during activity. 



Recent work on Skeletal Muscle. Quite recently the inquiry has 

 been pushed a good deal further by Verzar' 3 ', who investigated the 

 time relations of the oxidation as compared with the muscular 

 activity. His technique was very different from that of Chauveau 

 and Kaufmann ; armed with the modern methods by which it is 

 possible to work on minimal quantities of blood, he made a muscle 

 nerve preparation of the cat's gastrocnemius muscle. The general 

 relations of the dissection will be seen in the accompanying figure. 



FIG. 39. G = gastrocnemius muscle. Sc- sciatic nerve. A = artery. Vf= femoral vein. 

 Fs = saphenous vein. P = pipette. M"=myograph. 



The veins which contributed to the femoral vein below the 

 saphenous were all tied with the exception of that which came 

 from the gastrocnemius muscle. A cannula was introduced into the 

 saphenous vein, and when a sample of blood was required the clip 

 was removed from the saphenous vein and placed on the femoral 

 vein above the junction of the two vessels. The blood was collected 

 into a graduated 1 c.c. pipette so that the time taken for 1 c.c. to flow 

 through the muscle might be measured. The blood was prevented 

 from clotting by the intravenous injection of hirudin. The muscle 

 was thrown into contraction by the application of an electrical 

 stimulus to the sciatic nerve. The muscle lifted a weight, doing 

 about 70 grm. cm. of work at the beginning of each tetanus. 



The following diagrams with the figures on which they are based 

 show quite distinctly the time relations of the tetanus and the call 

 for oxygen. The latter takes place : 



