326 T. HOUGH AND C. E. HAM 



processes of excretion, has not been made good by the taking of food. 

 Under these circumstances, the injection of any fluid quickly increases 

 the volume of blood, and so improves the circulation through all 

 organs the muscles included. Perhaps, also, by reducing the 

 osmotic tension of the plasma, waste products which have accumu- 

 lated in the muscle during the inactive winter period are removed, 

 so that the excised muscle becomes capable of greater work. This 

 obviously suggests a useful method of improving the physiological con- 

 dition of frogs used for laboratory experiments during the winter 

 months. 



SUMMARY. 



1. Injections of water, Ringer's fluid, and 10 per cent ethyl alcohol 

 into the lymph sacs of a frog improves the working capacity of the 

 skeletal muscles and delays the progress of fatigue in the isolated 

 muscle. 



2. The effect is largely independent of the solution and seems to 

 be due to the increase of the circulating medium, or to the reduction 

 of osmotic tension in the blood plasma, or to both of these causes 

 combined. 



3. The improvement in the working power of the muscle, which 

 Lee and Salant observed after injections of 10 per cent alcohol, is 

 not due to the alcohol. 



