366 



(Fig. 1). This reaction is soon succ^eeded by complete insensibility 

 for stimulation. 



2. If the ninscle has been put into a veratrin-solution weaker 

 than 1 : 1000, but stronger than 1 : 100000 a series of curves is 

 obtained, of which either the first or a following gives the strongest 

 picture of (he typical veratrin-poisoning, after which this effect 

 diminishes till it finally disappears, so that the muscle, just as before 

 the [)oi8oning, responds to the stimulation with a single, rapid 

 contraction, if at least it has not become insensitive, before this 

 stage has been reached. 



3. If solutions of 1 : 100000 and weakei' are employed, a definite 

 effect of the veratrin-action is obtained, which can maintain itself 

 for hours together when the preparation is regularly stimulated. 



There are three hypotheses which might explain the process 

 described sub J and 2. 



A. When the muscle has absorbed a certain quantity of poison 

 and gradually diminishes the effect of this by its contractions — no 

 matter how this happens — it is no more able to stand the influence 

 of veratrin again. 



B. The quantity of poison in the solution is not sufficient to 

 supply the quantity abolished by the muscle. 



C. In the period between two contractions the muscle modifies 

 its character in such a wa)', that it grows less sensitive to veratrin - 

 influence. 



Hypothesis A may be omitted : a muscle once poisoned by veratrin 

 can very well be influenced by veratrin-action again, after the 

 veratrin -effect has been abolished by repeated contracting (e.g. by 

 frequent stimulation), as the experiment teaches. 



Hypothesis B may also be omitted, because von Fhey's ') experi- 

 ments show, that minimum quantities are already sufficient to poison 

 a muscle. Therefore the hypothesis remains, that the muscle alters 

 its character in the period of time between two stimulations, a 

 modification which can only be attributed to the action of veratrin, 

 for if all circumstances are left unchanged and only the verafrin- 

 conceutration is alteied, a definite rate of poisoning occurs, which 

 appears to be constant (third process). 



Evidently there exists, besides the veratrin-effect on the striated 

 muscle, causing the well-known second shortening, another action, 

 having an unfavourable influence on the effect first-mentioned, and 

 causing a rapid and exhaustive effect in strong concentrations, in 



^) Sitzungsber. der Physik.-Med. Geselsch., Wurzburg, 1912. 



