1910.] Nicotine and other PyHdine Bases uj^on Muscle. 



341 



commercial curare was required for the complete " curarisation " of an 

 average sized frog (20 to 30 grammes) ; a similar effect, on a similar frog, was 

 produced in a shorter time by the same volume of a 0"01-per-cent. solution of 

 Boehm's preparation.* The latter was thus known to Ije upwards of 100 

 times as active as the commercial i)roduet, as judged of )jy its specific action 

 as regards blocking of the impulse from nerve to muscle. 



As regards direct effects upon muscle, both prepai'ati(jns of curare were 

 what we are accustomed to call " slightly active," i.e. in 0"l-per-cent. solution 

 the contractility of nmscle was not abolished in lialf an hour (fig. 8). Boehm's 

 curarine in 0"l-per-cent. solution was rather more active than the solution of 

 commercial curare at the same concentration (but considerably less active 

 than nicotine at O'l per cent, and even O'Ol per cent.); this difference of 

 activity between the two samples of curare was much below the difference as 

 judged by the specific " curarisation " test. 



Fig. 8.— Effect of curarine iodide, 1 per 1000, or 0-0024 n. (Boehm.) 



The AnlH(jonism of Nicotine hy Curarine. 

 Langley has pointed out the antagonism of nicotine by curare ; our 

 nicotine and curarine experiments are confirmatory of this antagonism, and 

 bring out approximately a quantitative relation between them. We find by 

 immersing muscles in mixtures of nicotine and curarine solutions in which 

 the proportion of N : C by molecules is varied from 2 : 1 to 160 : 1, that 

 the typical nicotine effect is unfailingly abolished when 30 molecules of 

 nicotine are in presence of 1 molecule curarine. In this instance the 

 nicotine was taken at nf 500, i.e. well above the strength required for 

 a characteristic effect, as, moreover, was indicated by a simultaneous control 

 experiment. The curarine in the mixed solution was at the concentra- 

 tion ?i/16000, i.e. far below a concentration at which curarine by itself can 

 act upon muscle. As shown above, curarine in /t/424 = 1/1000 does not 



* Langley's " curare " seems to have been weak, probably the " pot curare " that has 

 replaced " calabash curare " in the market during the last 20 years (R.S., p. 176) ; he 

 antagonises 4 milligrammes nicotine by .50 milligrammes of curare, and refers to this as 

 being two or three times the amount required to prevent the " sciatic causing contraction 

 of the muscle. ' 



2 E 2 



