1909.] Observations on the Rate of Action of Drugs, etc. 215 



Graph 3. 



Fig. 15.— Quinine, «/2000. 



The observed and calculated times compare as under : — 



Times (obs.). 



Times (calc). 



53 



53 



35 



33-8 



22 



19 



IG 



17-4 



15"5 



17-4 



15 



15-8 



10-5 



11-2 



The concordance is not so good as in the two preceding series ; this is to be 

 expected, partly from the high temperature coefficient and partly on account 

 of the difficulty of ascertaining the end-point. 



Aconitine Hydrocldoride. 



We selected aconitine as being the most powerful poison known to us, 

 acting upon muscle at a dilution reaching »/100000. In our first trials at 

 strengths of ?t/1000 and n j 2000 we found that it was necessary to cleanse 

 the vessels with great care, otherwise an evident aconitine effect might present 

 itself as a fallacy. 



The effect of low temperature was particularly striking. The toxic 

 action of solutions ?i/10000, and even of 7i/2000 and 7i/1000, was completely 

 suspended, while the temperature of solution, and presumably of muscle, was 

 at 7° to 8°, but made its appearance as soon as the temperature was raised. 



We have already commented on this remarkable result as affording evidence 

 of the chemical factor as distinct from the diffusion factor. 



VOL. LXXXII. — B. S 



