Physiology. — “A Quantitative Inquiry into the Antogonism Pilo- 
carpin-Atropin on the Surviving Cat-qut’. By Prof. W. Storm 
VAN Leruwen and Miss C. van DEN BROEKE. (Communicated 
by Prof. R. Maenus). 
(Communicated at the meeting of April 23, 1920). 
At our Institute we often felt the want of a correct physiological 
determination of the strength of atropin-containing solutions. With 
one of the usual methods which is based on the property of atropin 
to restore pulsation after the muscarin-standstill of the frog’s heart 
our results proved unsatisfactory. We, therefore, endeavoured to find 
a method that should yield more reliable results, viz. by taking the 
antagonism of atropin on the action of pilocarpin on the surviving 
gut, as an index of atropin-action. 
Laborious investigations of this antagonism have been carried out 
by van Lipra pe Juupe'). His publication also contains complete 
references on this subject. 
He conducted his experiments as follows: The contractions of pieces of a rabbit's 
small intestine were recorded on a kymograph. The pieces of the intestine were 
suspensed in vessels of 15, 75 and 150 ce. The experimenter disposed of an appa- 
ratus that enabled him to work with twelve pieces at a time. The vessels were 
filled with Tyrode solution to which varying quantities of pilocarpin were added. 
As v. Lior De Jeupe used vessels of varying sizes he was able to vary in his 
experiments the dosis of pilocarpin and atropin, with or without varying at the 
same time the concentrations of these drugs. As soon as, in his experiments, the 
pilocarpin had produced a contraction of the isolated gut, every 20 seconds !/4 c.c 
of a definite atropin-solution was added. This was repeated until an atropin action 
was clearly noticeable. 
VAN LiptH DE JEUDE points to several errors to be guarded against in a similar 
investigation. The rate at which the oxygen bubbles through the vessels during 
the experiment, should not vary too much, since a strong current of oxygen causes 
the atropin to mix sooner, and consequently an antagonistic action to manifest 
itself sooner than a weak current will do. The concentration of the atropin-solution, 
of which always '/, c.c. is added, should be the same in all experiments, other- 
wise erroneous results will be obtained, etc. 
With due precaution v. Lipra bE Jeupe undertook a series of 
1) A. P. v. Lint pe Jeupe. Quantitatieve onderzoekingen over het antagonisme 
van sulfas atropini tegenover hydrochloras pilocarpini, salicylas physosligmini en 
hydrochloras muscarini (Griibler) op overlevende darmen van zoogdieren. Acad. 
Proefschrift. Utrecht, 1916. 
