941 
bloodcells the bloodpressure is heightened to 108 mm. Hg. again, 0,005 mer. 
of adrenalin yields a slight rise of the bloodpressure and 0,02 mgr. of adrenalin 
a considerable one. The decreased adrenalin action after the blooding did, therefore, 
not depend only on the removal of plasma, but also on the fall of the bloodpressure, 
for after this fall had been checked, adrenalin acted better, though still less than 
at the commencement of the experiment. 
These experiments lend support to our supposition that in serum 
substances occur that intensify the adrenalin action; when the serum 
has been substituted by Tyrodesolution + red bloodcells the adre- 
nalin action diminishes, if namely a large amount of blood has 
been deprived in this way. This diminution of the adrenalin action 
manifested itself as well when the primary adrenalin action had 
decreased the blood pressure (exp. 1 and 4,) as when it had raised it 
(Exp. 3). The decrease of the adrenalin action appears, no matter 
whether the bloodpressure is lowered by the plasmaphaeresis or 
not. In exp. 3. 0,01 mgr. of adrenalin is inactive although the 
bloodpressure is as high as 150 mm. Hg., while previously with a 
bloodpressure that was only a few millimeters of mercury higher, 
0,005 mgr. of adrenalin brought about a distinct increase. 
It is essential to emphasize the fact that after removal of plasma 
adrenalin acts less strongly, also when the bloodpressure is high, 
because Pryton Rous and Witson') and Bareirer*) have recently 
demonstrated that in dogs and in cats the adrenalin action is weak- 
ened, when the bloodpressure becomes considerably lower in conse- 
quence of bleeding. We observed this phenomenon only once, 
namely in exp. 4, in which, with a bloodpressure of 78 mm. Hg., 
0,005 mgr. of adrenalin was inactive, but after the bloodpressure 
was raised to 108 mm. Hg. through injection of red bloodeells with 
Tyrode, 0,005 mgr. of adrenalin produced an inconsiderable rise of 
bloodpressure. This, however, does not account for the insignificant 
adrenalin action after bleeding in our other experiments, because 
also when the bloodpressure after plasmaphaeresis amounted to 150 
mm. Hg. (Exp. 3), the adrenalin action was lessened. In fact if a 
decreased adrenalin action is to be attained only by a low blood- 
pressure, this must be very low, in Barsier’s experiments e.g. 10 
and 15 mm. Hg. 
By the deprival of serum and the addition of Tyrode-solution -+ red bloodcells 
the viscosity of the blood is of course diminished. In itself this would be a reason 
lj Pevrox Rous and G. Witson. The influence of etheranesthesia of hemorrhage 
and of plethora from transfusion of the pressure effect of minute quantities of 
epinephrine. Journ. of exp. med. 1919, p. 173. 
*) E. Baneten. Hemorragie et adrenaline. Soc. de Biol. Tome $2, p. 758, 1919. 
