S i6 



COMPARATIVE ELECTRO-PHYSIOLOGY 



responses seen in the first series are found to be abolished 

 when the nerve has been subjected to strong vapour of 

 ammonia for some time. It should be mentioned here that 

 this abolition takes place under the action of a strong dose. 

 When highly diluted with air, the vapour may cause a 

 temporary exaltation. 



In the next figure (fig. 317) is shown the effect of morphia. 

 After the application of this solution for a certain length of 



time, the response is seen to 

 'be abolished. The strength 

 of application which brings 

 about this abolition I find to 

 vary according to the condi- 



FIG. 316. Photographic Record 

 of Effect of Ammonia on 

 Mechanical Response of Frog's 

 Nerve 



First series of responses are nor- 

 mal. Second series show effect 

 of ammonia in practical aboli- 

 tion of response. 



FIG. 317. Photographic 

 Record showing Abolition 

 of Mechanical Response 

 of Frog's Nerve by Action 

 of Solution of Morphia 



tion of the nerve. Another agent by which the mechanical 

 response of the nerve is found to be abolished is aconite. 

 And it is of special interest to note that I have often found 

 this to act as an antidote, for the revival of response 

 previously almost completely abolished by morphia. The 

 condition of the nerve here also appears to be a determining 

 factor in the mutually antidotal action of these two poisons. 

 A strong application of alcohol after long-continued action 



