634 
little when the concentration rises. We were naturally led to sus- 
pect that the small augmentation of the atropin-dosis, observed by 
vAN LiptH DR Jeupe with a rise of the pilocarpin-dosis, would take 
place at the very beginning of the concentration-action-curve, i. e. 
we suspected that with very small doses of pilocarpin, the increase 
of the atropin doses would be relatively large when the pilocarpin- 
concentration increases, while in the higher pilocarpin-concentrations 
the quantum of atropin necessary for the antagonism would be 
the same. 
In another series of experiments we have attempted to solve this 
problem. 
We used pieces of a cat's gut contained in vessels with 75 c.c. 
of Tyrode solution. At the commencement of the experiment, several 
times pilocarpin was added to these guts (and after this the pilo- 
carpin was washed out again) till the sensitiveness of the gut to this 
poison had become constant. This done, we ascertained how much 
atropin had to be added to arrest the pilocarpin action almost com- 
pletely after 3 minutes. 
In this procedure the intensity of the ‘oscillatory movements” 
was not regarded, but the pilocarpin-action was considered to be arrested, 
when the base of the curve had nearly resumed its normal niveau again. 
It became evident from these experiments that the quantum of 
atropin necessary for arrest of the pilocarpin-action does not depend 
on the quantity of the pilocarpin doses, but on the intensity of the 
action incited by the pilocarpin, that is to say, when at one moment 
in one and the same experiment a given dosis of pilocarpin exerts 
a weak action and has a stronger effect at another moment, then 
the quantum of atropin required in the first case will also be smaller 
than the one required in the second. The same holds both for the 
action of pilocarpin upon one and the same piece of gut, and upon 
different pieces. So, if at a given moment the sensitivity of the gut 
to pilocarpin, is such that 0.1 mgr. of pilocarpin produces a weak 
action, the quantity of atropin, required to arrest this action, will 
be equal to that, required to arrest the same weak pilocarpin-action 
if at another moment it is elicited by a dosis of pilocarpin as small as 
0.01 mgr. In all we have performed 33 experiments in this manner. 
When arranging these experiments so as to place all the cases of a weak 
pilocarpin action in one group, in another all the cases of a mode- 
rately strong pilocarpin-action, and lastly all the cases of a sub- 
maximal pilocarpin-action (corresponding with the point c of the 
concentration-action curve of fig. 2) in a third group, it appeared 
that the average quantum of atropin required for the antagonism 
