391 
to investigate the action of different quanta of morphin on the dog. 
The results obtained were that doses smaller than 1,5 mgr. had but 
little narcotic effect or none at all; that 1,5 mgr. yields a distinct 
action, 2,5 mgr. a narcotic action, which is considerably stronger, 
while the effect of 5 mgr. differs little from that of 2,5 and finally 
that, as said above, the influence exerted by 10 mgr. is about 
equal to that of 5 mgr. If we should draw a curve of this peculiar 
relation between action and concentration, a so-called concentration- 
effect curve, it would again rise abruptly at the outset and then 
again proceed about horizontally, just like the curve representing 
the action of morphin and of scopolin on the reflexes of the rabbit. 
After it had thns appeared that the action of 5 mgr. of morphin 
+ 0,5 mgr. of scop. agrees with that of 10 mgr. of morphin, but 
still is not greater than that of 5 mgr. of morphin alone, we tried 
to find out whether the action of smaller doses of morphin was 
intensified by scopolamin. An injection of 2,5 mgr. of morph. per 
ke. was given to two dogs I and II, and to two other dogs III 
and IV 2,5 mgr. of morph. + 0,5 mgr. of scop. per kg. 
was administered. The narcosis of dog IIl was as profound 
aso tnat ol L and’ Tt; - but that of IV was considerably less 
profound than that of I and [l. The inevitable conclusion, therefore, 
is that scopolamin inhibited the action of morphin, so it did not 
bring about “potentiation” at all. This result was confirmed by a 
series of experiments with dogs, in which some received 1,5 mgr. 
of morphin and others 1,5 mgr. of morph. + 0,5 mgr. of scop. 
The narcosis with the former group was invariably more profound 
than that of the second. 
It follows from these experiments that although narcotic symptoms 
are generated by scopolamin in doses of from 0,5 to 1 mgr. per 
kg., this poison has also a distinct stimulating effect on the dog. 
When small doses of morphin are mixed with scopolamin, the result 
is the algebraic sum of the effects of the two components and the 
narcotic effect of the morphin antagonizes in part the stimulating 
effect of the scopolamin. With larger doses of morphin the stimulat- 
ing effect of the secopolamin falls back, while it would seem that 
the narcotic effect of morphin is sometimes reinforced in a small 
degree by the scopolamin, however in such a small degree that it 
cannot be called “potentiation”, but is merely to be considered as 
a simple addition. 
Upon the evidence founded upon very accurate experiments 
SCHNEIDERLIN concluded that in men the scop-morph. combination 
produces a real ‘“‘potentiated’”’ narcotic effect. He administered a rather 
26 
Proceedings Royal Acad. Amsterdam. Vol. XXII. 
