1 900- 1 . 



Observations on Blood Pressure. 



the heart under a stream of cold water. But although the heart 

 was beating when the chest was opened it was practically empty, 

 and a wound made in the left ventricle did not bleed to any extent. 

 In this case death resulted from 9 minims of Scheele's acid given 

 to a twelve pound dog in three doses within four minutes. The 

 result was death from respiratory failure, but before this occurred 



1 8a 



18 



M 



Tracing XXXIX.— q/26. — Repeated doses of H.C.N. 18 Second dose given. Respiration excited. 

 i8a Pulse slowing. 



there was great and repeated stimulation of the respiratory centre. 

 As with many other drugs, a small dose produces one effect and a 

 larger dose the opposite — stimulation in the one case, paralysis in 

 the other. It is the first stage, that of stimulation only, which is 

 produced by the dose recommended by Professor Hobday. N. 

 Grehaut^ showed that repeated small doses of H.C.N, produced powerful 

 stimulation of the respiration. After the injection of 5 c.c. of a 1/10,000 



19 



vv^Vvy^^^'^^^'^^ 



Tracing XL. — 9/17.— Repeated dose of H.C.N. 19 Third dose. Respiration excited and then 

 slowed and stopped about 20. Pulse slowed, pressure fell to zero. 



solution of pure H.C.N, into the jugular vein of a dog weighing lO 

 kilo., the respiratory movements immediately became more ample 

 and soon again returned to their ordinary rhythm. He found 

 that 7/1,000 c.c. of pure H.C.N, killed a 9 kilo, dog in seventeen 

 minutes. 



Next, single doses just sufficient to produce death were given to 

 several dogs in order to note the sequence of events. An animal 

 weighing about sixteen pounds was given 10 minims of dilute H.C.N, 

 (equal to 5 minims of Scheele's acid) hypodermically. He had 

 already had 3 minims half an hour before. The pulse rate, blood 



I Physiolog. Researches on H.C.N. Archiv. de Physiol, 1890, p. 133. 



