1909.] Observations on the RaH^, of Action of Drugs, etc. 



209 



contractility under the influence of the drug at the lower and higher 

 temperatures ; To and Ti the respective ahsolute temperatures. This takes 

 length of time as expressing the rate of chemical change, i.e. the rate with 

 which the drug reacts upon the living muscle. The shorter the time, the 

 greater the rate. 



Put into words, formula (3)' states that the logarithmic increment of 

 chemical change (which in our observations is represented by the logarithmic 

 decrement of time of complete intoxication) varies as the logarithmic 

 increment of absolute temperature ; the graph of this relation is a straight 

 line, which affords a convenient means of representing a series of results ; 

 for this purpose we have taken time along the abscissa, temperature along the 

 ordinates. 



We have selected as typical substances of widely differing toxicities : 

 ethyl alcohol, chloroform, quinine hydrochloride, and aconitine hydrochloride, 

 taken of concentrations such as to bring about the abolition of muscular 

 contraction within convenient lengths of time at temperatures ranging from 

 7° to 27°. (According to our preliminary observations, the relative toxicities 

 of these substances taken on the molecular scale are : Alcohol = 1, 

 Chloroform = 100, Quinine = 2000, Aconitine = 20,000.) 



The accuracy of our time-measurements was always subject to an error of 

 about half a minute by reason of the difficulty of determining the end- point 

 of the abolition of contractility ; this error was aggravated in observations 

 taken at low temperatures. 



(1) Ethrjl Alcohol. 



Alcohol, sold as " pure absolute," was purified as follows : A stick of 

 sodium hydrate was dissolved in the spirit and the whole heated in a reverse 

 condenser for one hour in order to saponify the esters, and resinify the 

 aldehydes ; it was then fractionated, the middle portion, boiling at 

 78°"9 (corr.), being retained. Two density determinations gave the following 

 results: S.G.^^/^^ = 0-81046 and 0'81045 respectively, which corresponds to 

 94*5 per cent, per weight alcohol. 



It has been shown in previous investigations that this method of purifica- 

 tion removes all impurities other than water, which for our purpose is not 

 material. The alcohol was made up to normal solution : 46 grammes 

 per litre of 0-6-per-cent. saline in tap water. 



