DAVID CERNA—PHYSIOLOGICAL ACTIONS OF SPARTEINE. 
67 
But the more frequent phenomenon observed regarding the pulse-rate, 
is the slowness produced by sparteine when given particularly in thera¬ 
peutic or large amounts. This decrease is quite distinct, and is, as already 
stated, generally accompanied later in the poisoning with a remarkable 
increase in the size of the pulse-curves. 
From a physiological standpoint, there are also several ways in which 
a reduction of cardiac rate may be brought about by drugs: (a) a para¬ 
lyzing influence exercised on the heart muscle; ( b) stimulation of the 
intracardiac inhibitory ganglia, or of the medullary cardio-inhibitory 
centers through the vagi nerves; (c) paralysis alone of part or of all the 
accelerator-nerve apparatus. 
Under the action of sparteine, the fall of cardiac rate occurs not only 
in the normal dog, but also in animals in which division of the vagi has 
been practiced beforehand, as well as in those instances in which the 
heart has been separated from all nervous connection by section of both 
pneumogastrics and of the cord in the cervical region. From these re¬ 
sults alone it could be inferred that the action of the drug was mainly of 
cardiac origin, but the inference would be illogical indeed. For while it 
can not be denied that direct cardiac influence is a prominent factor in 
the production of a slow pulse by sparteine, there can be no doubt, on 
the other hand, that the*agent likewise acts on the nervous mechanism of 
the heart, to cause the same effect. 
As is observed in Experiment XVI, a current of electricity sufficiently 
powerful to produce total arrest of the heart, in 10 and 6 seconds, when 
Fig. M. 
Tracing III.—Dog weighing 7 kilos, under the influence of curare. Gave 0.1 
gramme of sparteine sulphate intravenously. 
applied to the central and peripheral ends of a cut vagus, respective^, 
caused in the sparteinized animal an almost immediate stoppage of the 
cardiac viscus. In other words, in the one instance 10 and 6 units, 
respectively, of a certain faradic current, applied to the central and 
