352 URTICA0EJ3. 



2nd. — The breathing Is accelerated for a few minutes after 



the injection of the poison, but afterwards the 

 number of respirations gradually decreases until 

 death takes place. 



Srd, — The final effect of the poison is to stop the heart in 



systole* 



In the poisoned frogs the ventricle was contracted, empty, 

 hard and white. In the mammal the left ventricle was smaller 

 and harder than usual, the right ventricle less contracted and 

 full of dark blood. Before final stoppage the heart symptoms 

 may be divided Into several stages. In mammals, at a certain 

 period after the injection of the poison, a sudden want of 

 rythm was observed, the heart beating very irregularly. After- 

 wards the pulsations became more and more feeble, with 

 occasional stronger contractions, and finally periods of great 

 depression alternating with periods of stronger pulsation were 

 observed. In all cases a few auricular pulsations occurred after 

 stoppage of the ventricles. It was remarked also that pulsation 

 could be re-induced by mechanical or electrical stimulation of 

 the heart muscle. 



In the frog the first effect of the poison on the heart is a 

 very marked doubling of the pulsations. Whereas in the 

 normal condition the auricular contraction immediately precedes 

 the ventricular, and is shown on the pulse tracing by a slight 

 hitch in the curve of the total pulsation ; in the poisoned animal 

 the two pulsations are separated by a marked Interval, and finally 

 the auricular curve becomes so mai'ked as to equal or even 



in 



o 



In the second stage the ventricle only contracts once to 

 several auricular contractions, that Is, it only contracts when 

 it has become sufficiently distended with blood to excite con- 

 tractions. 



In the last stage the strength of the auricular contractions 

 gradually decreases, the ventricle remaining immovable, 

 empty, and contracted. The authors conclude that the poison 

 acts upon the intracardiac ganglia and not upon the central 

 nervous system. 



