286 



Drs. T. Cash and G. F. Yeo. 



[June 14, 



The value of the curve to the first distinct fall of the lever is "13", 

 but relaxation occurs slowly after this. 



Muscle. Weight. Latency. Length, of 



° J curve. 



Gastrocnemius . . 30 grms 'Oil" .... *13" 



The maximum of contraction is reached in about , 03". 



•018" 



Table V. — Kitten (two months old). 



Muscle. Weight. Latency. 

 Gastrocnemius .... 30 grms 



Birds. 



The muscles of three birds were examined. 



Table VI. 



Animal. 



Muscle. 



Weight. 



Latency. 



Length of curve. 



Hen 



G-astrocneniius 



30 grms. 



•0204" 



•116" 





- ". 



30 „ 



•012" 



•074" 





30 „ 



•on" 



•083" 



Blackbird . . 



Gastrocnemius 





•0125" 



•081" 









•014" 



•087" 





Max. of biceps brach. "045". 





We will not recapitulate the results given in the tables further 

 than by drawing attention to the extremes of the values obtained. 

 In the December frog we found the triceps directly stimulated had the 

 shortest latency ("0114"), whilst the hyoglossus had the longest '015". 

 The muscles of the trunk hyoglossus and rectus abdominis (compound 

 but parallel fibred muscle) exhibited longer latencies than did the 

 muscles of the extremities ; the muscles of the arm again longer than 

 those of the leg. 



In forming our conclusions concerning the duration of the latent 

 period of contraction of skeletal muscles, and the variations it is 

 subject to, we must refer repeatedly to our former paper, of which 

 this, as has been said, may be regarded as the continuation. 



The latencies of gastrocnemii of Bana temp., examined between 

 January and April, and selected at random, varied between wide 

 limits, namely from "008" — , 0208' / . These values include also measure- 

 ments taken from curarised gastrocnemii, but as we have already 

 pointed out, the small dose of curare employed appeared in no way to 

 cause any divergence in reaction of the muscle from the normal. In 

 this respect our results confirm the view expressed by Pniiger. In 



