1906.] Recently -Discovered African Arrow Poison. 



17 



A tracing of the normal blood pressure and of the respiration was taken in 

 all cases before the poison was injected. This substance was injected either 

 into the femoral or jugular vein in the cats and into the marginal vein of the 

 ear in the rabbits. 



The poison was also tested with regard to its action upon the frog's heart 

 and voluntary muscle. The solutions were made with Einger's solution and 

 applied with a brush. The heart beats were recorded by means of a lever in 

 the usual way. The down-stroke represents systole. 



The effects of injection of the poison upon the vascular system and 

 respiration will first be described, after which the effects of the following 

 procedures upon these systems under the influence of the poison will be 

 discussed : — 



Abdominal compression. Excitation of depressor nerve. 



Section of vagus — Section of spinal cord. 



a. Before injection of poison. Section of splanchnic nerves. 



b. After „ Excitation of splanchnic nerve. 

 Excitation of vagus. Previous injection of apocodeiu. 



Finally, the action of the poison upon the frog's heart and voluntary 

 muscle will be considered. 



Action upon the Vascular System and Respiration — Effects of the Poison alone. 



Blood Pressure. — Almost immediately after the commencement of the 

 injection, or a few seconds later, the blood pressure rises rapidly, but not 

 suddenly. In about 10 seconds it reaches a height of about 30 to 

 40 mm. Hg above what it originally was. During the next few seconds the 

 pressure curve falls a trifle, and is liable to be interrupted by sudden small 

 depressions. 



From this point there is a very slow, steady rise in the pressure, the 

 maximum height being attained in a minute or more according to the dose. 

 The height is now from 10 to 20 mm. Hg greater than the maximum of the 

 first rise. From this point the pressure curve gradually falls for 

 two minutes or more, the incline being much steeper during the last 

 half minute. 



The curve is now frequently interrupted by sudden drops in the pressure, 

 the latter recovering itself each time less and less, till it reaches its lowest 

 point at death. With small doses the effect is not so marked, and the final 

 fall of pressure is very gradual, irregular small fluctuations taking place as 

 the curve drops. 



VOL. LXXVIII. — 13. C 



