316 PROTEIN POISONS 



traced upon blackened paper. Injection into the external 

 jugular ,vein of the soluble portion of 100 mg. of the crude 

 poison was followed immediately by a slow decline in blood 

 pressure, amounting to from 6 to 8 mm. Hg.; after about 

 twenty seconds the fall became rapid, passing from a normal 

 of about 72 mm. to about 20 mm. Synchronously with 

 the fall in pressure the heart-beat was at first slightly 

 accelerated, passing from 138 or 140 to 144, but when the 

 pressure reached the low point the heart-rate dropped to 

 92. The respiration was but little changed in rate, becoming 

 slightly slower with the fall in pressure, but the strength 

 was considerably decreased, neither inspiration nor expira- 

 tion being as complete as normal. 



The blood pressure was slow to recover. In some instances 

 there was an increase of only a few millimeters after thirty 

 minutes. When under the full influence of the poison, 

 stimulation of either the sciatic or the great splanchnic 

 nerve with the induced current elicited no response, showing 

 peripheral paralysis of the vasomotors. In pithed animals 

 (with the brain and cord destroyed) the effect upon blood- 

 pressure was the same as on whole animals, only that the 

 initial pressure being small, the fall did not measure so 

 many millimeters. "That this action was peripheral to 

 the ganglia along the course of the constrictor fibers was 

 proved by the use of large doses of nicotine, sufficient being 

 given to paralyze them. When this stage was reached an 

 injection of the poison still produced the characteristic 

 fall. 



"The localization of the point of action of the poison 

 upon nerve ending, receptive substance, or muscle wall 

 was studied with the aid of nicotine, epinephrin, and digitalis. 

 The action of nicotine was greatly weakened by the previous 

 injection of the poison. Where before the poisoning, nico- 

 tine had given a marked increase in pressure in the charac- 

 teristic manner, following 300 mg. of the poison 5 mg. of 

 nicotine raised the pressure from 16 mm. to only 62 mm. 

 The heart-rate was increased by the nicotine in the usual 

 manner, from 120 per minute to 216. The pressure curve 



