544 



Functional (Edema in Frog's Muscle. 

 By M. Back, K. M. Cogan, and A. E. Towers. 



(Communicated by J. Barcroft, F.B.S. Beceived February 18, 1915.) 



The following experiments resulted from an observation that after 

 stimulation of the gastrocnemius muscle on one side that muscle was 

 heavier by about 20 mgrm. than the muscle of the opposite side. 



Series 1. — To ascertain whether the above phenomenon was of constant 

 occurrence eleven experiments were performed in this series, together with 

 four control experiments. 



Method. — The frogs were pithed, the brain and spinal cord both being 

 destroyed. Electrodes were attached to the tendo Aehillis and under the 

 nerve as it entered the muscle. Care was taken to avoid haemorrhage as 

 much as possible, but we were not always successful in this. 



The preparation was stimulated by single induction shocks at the rate 

 of 40 per minute for 15 minutes. The muscles from the two legs were 

 then dissected out and weighed, usually within 15 minutes of the end of 

 the period of stimulation. 



The right and left legs were used indiscriminately. 



The following results were obtained : — 



Weight of muscle. 



Excess of weight of stimulated 

 muscle. 



Gain of weight per cent, by 

 stimulated muscle. 



mgrm. 



mgrm. 





409 



7 



1-7 



314 



-6-5 



-2-2 



160 



11 



8-0 



194 



12 



6 



206 



2-5 



1-2 



285 



-3-5 



-1 -1 



260 



3-7 



1-7 



260 



9-5 



3-8 



283 



7-9 



2-6 



263 



23 



9-2 



285 



-3-5 



-1-1 



Of these, the stimulated muscle was the heavier in eight cases and the 

 lighter in three, and in these three the disparity was trifling as compared 

 with many of the cases in which the stimulated muscle was the heavier. 



The following cases are given for comparison in which neither muscle was 

 stimulated : — 



