Physiology. — “Experimental Influence on the Sensitivity of various 
Animals and of Surviving Organs to Poisons’. (Part II). By 
W. Srorm vaN Leeuwen and Miss van DER Maps. (Commu- 
nicated by Prof. R. Magnus). 
(Communicated at the meeting at January 31, 1920). 
In the first part STORM VAN Leruwen and C. van DEN BROEKE have 
demonstrated that in the serum of various animals there are sub- 
stances which intensify the action of an alkaloid (pilocarpin) onthe 
surviving cat-gut. They also found a similar favourable influence to 
belong to cholesterin, to cerebron. to Witte's peptone, and in certain 
cases also to lecithin. We considered it useful to ascertain whether 
similar favouring substances also come into play in the action of 
poisons on the unimpaired animal. We also wished to make out 
how far the presence of inhibiting substances could be demonstrated 
in that case. Our first object was to inquire into the action of 
adrenalin upon the bloodpressure in the cat and in the rabbit. We 
did this because, as indeed we know from the literature, successive 
adrenalin-injections into the cat and the rabbit bring about a rise 
of bloodpressure every time of the same extent, so that a quantitative 
investigation is very well possible here. Before describing the general 
results of this inquiry we wish to report the first experiment we 
made in this direction. 
We wish to bring this experiment into prominence, since its process 
differed from all the others in a series of 50 inquiries, and 
because theoretically it seemed to us to be of some interest. 
In this experiment we ascertained the action of adrenalin on 
the decapitated cat. The smallest dosis that produced a distinct 
rise (of 14 mm. H.g.) in this animal, was 0-1 mgrm of adrenalin 
intravenously. Let it be observed here we shall recur to it later 
on — that this is an extremely large dosis for the minimum action. 
As has been said, this 0.1 mgrm of adrenalin produced a rise of 
blood-pressure of 14 mm. Hg.; in other cases of 12 mm. He, 
16 mm. Hg. and once as much as 28 mm. He. (fig. la). 
After it had thus been shown that 0.1 mgr. of adrenalin — dissolved 
in 1 ee. physiological water was constant in its action, the 
animal was again given 0.1 arenalin of the same substance, but 
61 
Proceedings Royal Acad. Amsterdam. Vol. XXII. 
