937 
in which the dialysate positively exerted an influence, was much 
less sensitive to adrenalin than all the others. The dosis of adrenalin, 
capable of producing a distinct rise of the bloodpressure in the 
decerebrated rabbit, ranged in all other experiments from 0.0007 to 
0.005, while in the one case, in which the dialysate actually inten- 
sified the action, the minimum quantity of adrenalin was considerably 
higher, viz. 0.01 mgr. It seems to us, that the reason why in most 
eases peptone, or its dialysate, does not intensify the adrenalin action 
in the decerebrated rabbit, is that in those cases the adrenalin, in 
consequence of the presence of certain substances in the serum, 
has already obtained the highest effect it can display under those 
circumstances (except in the experiment represented in fig. 4, of 
course); we believe that similar substances are not, or only to a 
less extent, to be found in the cat, so that in this animal peptone 
as a rule can play a part. Besides substances (hat exert an influence 
like peptone in our experiments, other substances must occur in 
the serum that are likewise very important, and that were wanting 
only in the cat of fig. 1, so that in this case the injection of serum 
resulted in this excessive increase of the adrenalin action. 
Anyhow, we think that our experiments have evidenced that the 
intensify of the adrenalin action on the bloodpressure in the decapi- 
tated cat does not only depend on the dosis of adrenalin and on 
the sensitivity of the animal, but also in a high degree on the 
presence in the serum of certain substances that increase this action. 
If such substances are wanting entirely or nearly so, as in fig. 1, 
the administration of normal serum can largely intensify the adrenalin 
action. In case the substances are wanting only in part, a similar 
increase of the adrenalin action — in a much smaller degree though — 
can be effected by peptone or still more by dialysate. As a rule 
so many intensifying substances seem to be present in the rabbit, 
that adrenalin exerts the strongest action possible under those circum- 
stances. In the experiment of fig. 4 this was not the case; here 
intensification of the action in the decerebrated rabbit could be 
reached with the dialysate. We are incompetent as yet to account 
for the fact that neither peptone nor its dialysate exerts the same 
influence in the narcotized cat as in the decapitated animal; there 
is, however, some analogy, viz. the symptoms of the anaphylactic 
shock are also less active, when the animal has been previously 
narcolized. 
If we are right in our conception that the action of adrenalin on 
the bloodpressure depends in several animals on the presence in 
the serum of these animals of substances that can intensify the 
