282 



Drs. T. Cash and G. F. Yeo. [June 14, 



As our desire was to obtain information of the latency actually 

 occurring in the muscle, we adopted the same plan in this series as 

 in our former experiments of stimulating the muscle directly. The 

 whole length of the muscle was introduced into the secondary circuit, 

 and a contraction registered, resulting from a maximal opening shock 

 of Du Bois Raymond's inductorium with a single pint Daniell cell. 

 The arrangement of the apparatus was similar to that employed in 

 our former series of experiments. 



We shall tabulate the mean results of a series of measurements of 

 curves obtained from a number of observations upon the animals 

 above mentioned, and we believe they will prove, that while the 

 latencies for different muscles of the same animal bear amongst 

 themselves certain proportion to the length of their succeeding 

 curves, we can by no means reason from one group of animals to 

 another what this relationship may be. 



Though the duration of the latency of each individual muscle varies 

 within certain limits in different frogs, we think we can vouch for the 

 correctness of the inter-relationship of the results furnished by the 

 various muscles employed in arriving at the averages given. Our 

 measurements confirm with considerable exactitude those obtained by 

 one of us from experiments made with the muscles of Bana escu- 

 lenta* in which another method was employed. We have naturally 

 regarded those results as most satisfactory, in which, by working 

 rapidly, we succeeded in obtaining representative curves of the whole 

 series of muscles furnished by one animal. 



Frog. 

 Table I. 



Rana Temporaria. — Examined in December. The average of the 

 measurements obtained from a large number of experiments is 

 given. 



Muscle. 



Weight. 



Length, of 

 latency. 



Altitude. 



Length of 

 curve. 



(Gastrocnemius . . 



10 grms. 



•0117" 



23 mm. 



•12" 





10 „ 



•0114" 



30 „ 



•112" 



Semimembranosus 



10 „ 



•0116 ,/ 



28 „ 



•119" 





5 „ 



•015" 



29 „ 



•18" 





5 „ 



•014" 



33 „ 



•167" 





5 „ 



•0124" 



185 „ 



•12" 



* Cash, " Journal of Anat. and Phys.," vol. xv. 



