218 



Buchanan 



the time indicated by the ascent of any one wave, so that in cord-cooling 

 experiments one can compare the frequency in corresponding waves in the 

 successive responses as in the experiment to which the table refers. When 

 there is little or no indication of waves in a record, as in the one repro- 

 duced in fig. 3, one frequency may give place to another abruptly, and in 

 cord-cooling experiments it is more difficult to select the corresponding 

 parts. But in the records obtained in several of such experiments made on 

 frogs in which the action of strychnine was not at its height and the 

 electrical reflex response non-serial, I have not been able to discover any 

 definite relation between the frequency of the rhythm and the temperature 



L. triceps of strychnine frog, F 160. Feb. 24, 1908. (Stimulation by 

 break induction shock to the L. sciatic, to the R. sciatic, or to the R. 

 brachial nerve.) Temperature of muscle constant (12° C). 



of the cord, when this was alternately raised and lowered. The wavelets 

 frequently are more marked when the cord is cool, i.e. the ascent and 

 descent of each wavelet is steeper (as is often the case also in the serial re- 

 sponses), but there is no constant lowering of fre<iuency in any part of the 

 record with cold. 



The waves, on the other hand, in all experiments I have made in which 

 the responses have been serial, vary in frequency in a very definite way 

 with the temperature of the cord. Thus in the experiment already cjuoted 

 we find that in the first five records, taken when the cord was at a tem- 

 perature of about 4° C, the frequency of the waves (estimated from the 

 four which alone appeared on each plate) was from 5"6 to 5 per second. In 

 the next three, in which the cord was nearly at 22° C, the frequency (again 

 estimating from the first four waves onl}^ although there were more on the 



