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Dr. C. Bolton. Physiological Action of a [Mar. 20, 



but the weakness increased, and finally it could not move at all. If rolled on 

 to one side it could hardly right itself. Finally it sank on to its side and, 

 after a few gasps, died one and a half hours after the injection. The respira- 

 tions were at first accelerated, but just before death they were slow. No 

 convulsions or twitchings whatever occurred, and no inspiratory dyspnoea or 

 chewing movements. 



Post-mortem. — The heart was in diastole, and the left auricle in a state of 

 fibrillary contractions. No clotting. 



Experiment 15. — Guinea-pig, weight 410 grammes. Subcutaneous injection 

 of 1/20 gramme of the poison (= 0*12 gramme per kilogramme). The 

 •symptoms began about the same time as those of the former pig. The 

 respirations were accelerated, and there was marked shivering and trembling. 

 The same weakness occurred, being most marked at first in the fore legs and 

 head. After passing through a stage of almost complete paralysis the 

 animal died one hour and ten minutes after the injection. 



Post-mortem. — The heart went on beating with irregular and spasmodic 

 contractions for ten minutes after death. No clotting. 



II. Blood-Pressure Experiments. 



In all the following blood-pressure experiments the poison was dissolved 

 in salt solution, which was filtered or centrifugalised before injection. In 

 the stimulation experiments the strength of the current was measured by 

 the distance in centimetres of the secondary from the primary coil. 



Poison Only. 



Experiment 1. — Cat, weight 2610 grammes. Poison 1/8 gramme 

 (= 0'047 gramme per kilogramme). 



Blood Pressure. — The curve is naturally divided into two parts, corre- 

 sponding to a sharp rise in the pressure with a succeeding fall, and a 

 second long and slow rise to a maximum with a succeeding fall till death. 



The pressure curve was unaltered for 12J seconds after the injection, and 

 the first rise then occurred. The pressure rose somewhat abruptly from 

 166 to 178 mm. Hg to 200 to 210 mm. Hg in 10 seconds, and during the 

 next six seconds it fell to 184 mm. Hg. The second rise of pressure was 

 more gradual, and attained its maximum point of 224 mm. Hg in the 

 succeeding 73 seconds, the pressure during this time having risen 40 mm. Hg. 

 From this point the curve gradually fell for 54 seconds, and then more 

 rapidly for the last 38 seconds of life. 



During the final fall there were three sudden descents of about 80 mm. Hg 

 in the curve, obviously due to heart failure. The heart recovered itself after 



