930 
a similair intense action. In order to make out whether perhaps 
this cat, which yielded such an abnormal reaction, was a castrated 
animal we first determined the sensitivity of a male cat to adrenalin 
(minimum active dosis 0.0005 mgr. of adrenalin); after this the 
animal was castrated and examined again three weeks later. The 
sensitivity to adrenalin was then the same as before. 
In one respect the cat with its abnormal reaction to human serum 
decidedly differed from all the other animals examined, viz. the minimum 
dosis of adrenalin just sufficient in this animal to produce a distinet 
rise of the bloodpressure, was exceedingly large (0,1 mgr.); whereas in 
nearly all the other animals examined this minimum dosis lies between 
0,005 and 0,0005 mer. of adrenalin, i.e. from doses 20 to 200 
times smaller. However this may be, it had appeared from this 
investigation that we may decide on principle that the influence of 
adrenalin on the bloodpressure in the animal does not depend only 
on the dosis of adrenalin and on the sensitivity of the specific 
organs, but also on the presence or the absence of substances in 
the serum of the animal that influence (in this case intensify) the 
adrenalin-action. 
We also tried to find out whether the serum contains substances 
that inhibit the adrenalin action, thus far with negative result. 
As stated above we never obtained a stronger action with a 
combination of serum and adrenalin than- with adrenalin alone, 
except in the one case alluded to. However, the results published 
in the first part of this communication regarding the action of pilo- 
carpin on the surviving gut and regarding the reinforcement of this 
action through Witte’s peptone, induced us to examine. ISO the 
action of peptone on the bloodpressure in the cat. 
The influence of Witte’s peptone itself on the bloodpressure in the 
cat and in the rabbit has been known for a long time. Many times 
already it has been shown in the literature that injections of rather 
large doses of peptone, from 300 to 500 mgr. per kg. animal, in 
cats and dogs, result in a marked fall of the bloodpressure with 
an ultimate standstill of the heart’s action. The same action was 
noticed by us with larger doses of peptone. It is worthy of notice, 
however, that our experiments demonstrated that very small doses 
of peptone, sometimes from 10 to 100 times smaller than those 
which cause death, are capable of intensifying the adrenalin-action 
in the decapitated cat, as appears from fig. 2. Here 0.001 mgr. of 
adrenalin yielded twice running a rise in the bloodpressure respectively 
of 14 and 16 mm. Hg. (a,b); after an injection of 0.1 ec. of Witte’s 
peptone 1°/, a similar quantum of adrenalin gave a rise of 18 to _ 
