1903.] Action of Ckoline, Neurine, Muscarine, and Betaine. 341 



Fig. 13 is given to illustrate the refreshing effect of a new transverse 

 section upon a small negative variation. It is not special to this 

 particular experiment, but illustrative of a general rule of procedure 

 that should be adopted in prolonged experiments. 



EXP. II. The two nerves of the same frog are similarly but simul- 

 taneously passed through the solutions. 



From Exps. I to V we think ourselves justified in estimating 

 betaine as belonging to the second of the three classes specified above, 

 i.e., as "moderately active." The electromobility of nerve, as 

 evidenced by the negative variation of its current of injury has been 

 abolished by betaine and restored by subsequent prolonged immersion 

 in physiological saline. 



The three following experiments show that muscarine has a similar 

 effect, but rather more pronounced ; the negative variation was per- 

 manently abolished in Exp. VI (also in Exp. IX). 



Exp. VIII, in which two nerves were similarly treated, is the most 

 complete ; it exhibits in both cases abolition by muscarine and recovery 

 by saline, three times repeated. 



FIG. 13 (Exp. I). 



V 



Exp. IX. In order to make comparison as closely as possible between 

 the individual members of the ptomaine group, we took four nerves, 

 as nearly as possible similar, and passed them simultaneously through, 

 each of the four test solutions and through physiological saline. 



The negative variation of nerve 1, immersed for 7 hours in musca- 

 rine, was completely and permanently abolished. That of nerve 2 for 

 7 hours in betaine was temporarily abolished. That of nerve 3, after 

 7 hours in choline, was unaffected, and after 27 hours diminished. 



