iv GENERAL PHYSIOLOGY OK NEEVOUS SYSTEM 213 



(d) Among the alkaloids, aconitine and veratrine iu 1 per 

 cent solutions rapidly abolish the current of action ; curariue, 



FIG. 138. Photograph. (Waller.) To show primary excitation of the nerve by a small amount of 



CO-2 applied between the two white lines. 



digitaline, and morphine diminish its activity; strychnine in- 

 creases it ; atropine and aconitine are inert. 



(e) Protracted tetanisation increases the current of action, i.e. 



CO-j 



FIG. 139. Photograph. (Waller.) Shows that a large amount of CO, acting on the nerve 

 during the light band, at first suspends the electrical reactions of the nerve and then has a 

 secondary exciting action. 



has an effect similar to that of CO., in small doses (Eig. 140). 

 Eroin this fact Waller argues that tetanisation of nerve is 

 accompanied by a development of C0 2 . 



