igoo-i.] 



Observations on Blood Pressure. 



225 



Tracing XLII.—q/aS.— Poisoning by H.C.N, seven minutes after fatal dose was given. P. 42 R. 

 7 pressure still maintained. 



-\^lnrtf\nAnf\AnJ\n^u^nAJ^J^^u^JV^^v^u^^u^i\nnnnfWlnnAIUVln^lJV\nAnlU\nl^^vu\lu^l^^ 



Tracing XLIII. — 9/34. — Poisoned by H.C.N. Last stage. Respiration already stopped. 



The sequence of events then from a small fatal dose is as follows : 

 First, preliminary stimulation of the respiration and pulse, the former 

 increasing in amplitude as well as in speed ; second, slowing of the 

 respiration and pulse, the pressure being maintained ; third, stoppage 

 of the respiration, pulse increasing in speed and pressure falling ; fourth, 

 pressure falling to zero, pulse remaining fast until death. 



I poisoned four dogs thus which had previously had a hypodermic 

 dose of morphia. In none of them did vomiting occur, nor convulsions. 

 One dog which had had no morphia or chloroform showed a strong 

 tendency to convulsions before death from a dose just sufficient to 

 obtain a fatal result. He vomited frequently. When the dose of the 

 driig is largely in excess of what is necessary to produce death, then 

 the animal almost at once passes into a state of convulsion. 



From these experiments it would seem that the dose of Scheele's 

 acid recommended by Professor Hobday, viz., i minim of Scheele's acid 

 to seven pounds of body weight, is a safe one in a dog. Such a dose, or 

 a lesser one, produces the stage of stimulation of the pulse and respira- 

 tion with no alteration in the blood pressure. The effect of the drug 

 soon wears off, and the animal seems to be none the worse. 



The next tracings show the effect of using H.C.N, when danger /tas 



occurred ^rora chloroform poisoning. A thirty-pound dog while vertical 



was given chloroform until the respiration stopped. In Tracing 44 the 



respiration stopped at 18. At 19, 4 minims of dilute H.C.N, were 



15 



