No. 2.] NERVE-MUSCLE EXPERIMENTS. 391 



each other. A satisfactory explanation of these facts has not 

 yet appeared, for the action of the Frog's larynx, even if it be 

 primitive in nature, does not appear to clear up the difficulties. 

 It is none the less interesting to note that a mammal whose 

 normal condition is with an open glottis, agrees in its responses 

 to stimulation of this organ with an amphibian whose normal 

 condition is with a closed glottis and who requires a voluntary 

 effort to get it open. 



The results of my study of the larynx and leg of the Frog 

 (and the few observations made on the leg of the Fowl and 

 Dog were entirely harmonious with them) clearly show that 

 {a) in this animal with every increase in the rate of stimulation 

 there must be a corresponding increase in the intensity of the 

 stimulus in order to get the same response, given by these 

 mechanisms to the initial low rate ; (p) that the influence of 

 an increase in the rate of stimulation is very like that of sul- 

 phuric ether and some other drugs, and (r) that Wedensky's 

 conclusions are only partly sustained, for there does not appear 

 to be a rate of stimulation, of influence so powerful that it can,, 

 like ether, entirely overcome the influence of increase of the 

 intensity of stimulation. 



The nature of the action of the rate of all kinds of stimuli 

 upon nervous tissue is as unknown as is the nature of the 

 influence which the rate of stimulation of the auditory nerve 

 has upon some of the muscular structures of the body. 



Of course the influence of the rate of stimulation is made- 

 manifest only when it progressively increases or decreases but 

 any rate whatsoever, has its own specific influence on the 

 propagation of nerve force while it lasts, so that changing the 

 rate merely makes apparent what already exists. 



That these two phenomena are intimately related, and that 

 they are grounded in some fundamental principle governing- 

 the existence of protoplasm, cannot be reasonably doubted. I 

 deeply regret that I have not been able to continue this study 

 to a more profitable termination, and the only reason for 

 publishing this fragment is the hope that it may prove sugges- 

 tive to some student and lead to a renewed search after the 

 effects of the rate of stimulation upon the nervous organization. 



