1903.] Action of Choline, Neurine, Muscarine, and Betaine. 325 



long soaking in physiological saline either a much-reduced deflection 

 or none at all. One exceptional case was recorded : on Plate 3653, the 

 effect of neurine hydrochloride for 1 minute is marked augmentation, and 

 the nerve on being tested the next day gave a good deflection. 



With a 30-minute bath of neurine hydrochloride the effect is usually 

 abolition immediate and final. In two cases a very small deflection 

 was recorded after the bath (Plates 3650, 3657), but in no case was 

 there any subsequent recovery. 



Pure choline, giving an alkaline reaction, was first tested in its 

 non-neutralised state. Immersion of the nerves for 1 minute had 

 always some effect, though not a marked one. Out of six records 

 taken, three show slight diminution, the other three slight augmenta- 

 tion. Four of the nerves were tested the next day and gave deflec- 

 tions, three of them large ones. The two other nerves were subjected 

 the same day to the longer bath 30 minutes with the result 

 recorded on plates 3666, 3667, viz., diminution to a mere trace within 

 20 minutes and abolition within 12 minutes; both, however, gave 

 small deflections on being tested the following day. In three other 

 experiments with a bath of 30 minutes the deflection was reduced, 

 markedly in two cases but there was partial recovery by the next 

 day. In the remaining case the diminution was less marked on the 

 record, but there was no after recovery. 



To obtain a 10-per cent, neutralised solution of choline, 1 vol. 

 20 per cent, choline was mixed with 1 vol. sulphuric acid n/10. The 

 effect upon nerve was less marked than in the case of pure choline 

 solution, which had shown one example of final abolition; the neutralised 

 solution gave, for the most part, diminution, but the recovery was 

 apparently more complete than with pure choline. In one experiment 

 (3672) the deflection next day was very small. 



Pure neurine non-neutralised was found as in former experiments to 

 be very toxic to nerve. At 10, 8, 5, and 4 per cent., immersion for 1 

 minute abolished all response. (The one exceptional case recorded, 

 Plate 3612, where the effect was only slight diminution, we cannot 

 attempt to explain ; at 2 per cent. 1 minute bath the deflection was 

 abolished, but there was partial recovery by the next day.) At 

 1 per cent. 1 minute there was diminution or abolition with 

 recovery. 



The results obtained with neutralised neurine were not very satis- 

 factory. The neurine was received from Messrs. Merck in a 25- 

 per cent, solution and required for the neutralisation 2 vols of normal 

 sulphuric acid. A glance at the table of experiments will show how 

 uncertain are the effects as compared with those of neurine hydro- 

 chloride. For instance, Nos. 3619 and 3620 were a pair of nerves 

 subjected to a 1 -minute bath of 8 per cent, neutralised neurine ; there 

 was little or no effect upon either nerve, they were then further 



