Changes in Action of some Alkaloids upon Frogs. 97 
58 (583) 
On fundamental changes in the action of some alkaloids upon 
frogs after cardiectomy or ligation of one aorta. 
By S. J. MELTZER. 
[From the Department of Physiology and Pharmacology of the Rocke- 
feller Institute for Medical Research.] 
At the last meeting of the American Physiological Society I 
reported that in cardiectomized frogs an injection of adrenalin 
will still cause dilatation of the pupil and an injection of strychnine 
will cause a tetanus. At the February meeting of this society I 
reported on the action of morphin on cardiectomized frogs. An 
injection of 10 or 15 mgr. of morphin in living, normal, medium- 
sized frogs causes at first no perceptible effect; after a few days a 
tetanus may set in, while there is at no time a depression. In 
cardiectomized frogs, however, an injection of 6 or 8 mgr. of mor- 
phin causes the appearance of tetanic symptoms in less than an 
hour. When 10 to 20 mgr. are injected the tetanus is preceded 
by a paretic state. After an injection of 25 to 30 mgr. the animal 
becomes paralyzed very early, to be interrupted later by only short 
weak tetanic movements. 
I have since found that also after the ligation of one aorta, 
especially of the right one, a tetanus will very frequently develop 
two or three hours after an injection of 10 or 15 mgr. of morphin; 
in some cases the tetanus may persist as long as twenty hours. 
In some cases two or three hours after the development of the 
spasmodic state the tetanus became temporarily interrupted by 
paralysis which lasted only 30 to 60 minutes. 
Since the beginning of April it often became difficult to obtain 
in cardiectomized frogs a tetanus; even with small doses of morphin 
the effect was in many cases complete paralysis, which set in very 
early after the injection. The same was true also of frogs with one 
aorta ligated. Here the heart might be seen beating forcefully 
for hours while the animal is completely paralyzed. The fact 
reminds one of the behavior of nerve and muscle irritability in 
spring frogs. 
Finally in a small percentage of cardiectomized frogs curare 
