Physiology. — "()n thp. progress of the verntrin-poisoniiig of the 

 striated frog-muscle'". Bj Akie Querido. (Coinmunicaled hy 

 Prof. G. VAN Rijnberk). 



(Communicated at the meeting of October 28, 1922.) 



1 . Concentration and dose. 



The nature of the action of veratrin on Ihe striated muscular 

 tissue still has not been sufficiently revealed, partly because of the 

 lack of knowledge of the conditions, associating the poisoning. 

 Repeatedly we read with various authors the remark, how fickle 

 and incalculable the veratrin-phenomenon is in its appearance, 

 seemingly independent of the quantity of poison used and the time 

 it could act. It is true in 1904 Mostinsky ^) examined the factors 

 cooperating in the formation of a definite shape of curve and he 

 succeeded in ascertaining the conditions incidental to this; the modi- 

 fications however of these conditions in the course of an experiment, 

 i. e. the alterations during the poisoning of the balance between 

 muscle-metabolism and poison-action of which the curve is a result, 

 are unknown as yet. Closely connected with this is the question, 

 in what way the shape of the curve corresponds with the rate of 

 poisoning of the muscle. On this subject we have some information, 

 that is two types of contraction-shape are distinguished, viz. the 

 type with two and with one top (fusion type), the latter of which 

 corresponds to a stronger rate of poisoning (Boehm "), Deelman *) ). 



In order to study these questions further, I irritated muscle- 

 nerve-preparations, after their immeision in a veratrin-Ringer-solu- 

 tion, by induction-shocks with so long a pause between the stimu- 

 lations, that the influence of a contraction on the following need 

 not be taken into account (three minutes). 



In this way 1 collected a great number of curves of veratrin- 

 poisonings for different concentrations of the poison. On contemplating 

 the modifications in the veratrinograin, we can get an idea of the 

 relation between cui-ve and rate of poisoning, for if a poisoning is 

 seen to progress in the direction of a diminishing or vanishing 



1) Arch, f exp. Path. u. Pharm., 51, 1904, 

 ') Idem 71, 1913. 



*) Gonti-ib. to Biology from the Amsterdam University 1914—15. 



