214 Transactions of the Canadian Institute. [Vol. VII. 



wrote :^ "We have in asphyxia increased blood pressure with Hvidity; 

 in fatal chloroform narcosis we have just the opposite, viz., diminished 

 blood pressure with pallor." They were both right probably, for, as 

 shown, the question of whether the pressure rises or falls in asphyxia 

 entirely depends on how the asphyxia is produced. It seems that as 

 long as efforts at respiration are made as in 28 the pressure is main- 

 tained but as soon as such efforts cease then the pressure falls. In 

 chloroform poisoning the respiratory centre is paralyzed and there are 

 no efforts at respiration and therefore the pressure may at once fall. 



Tracing XXIX. — 9/31. — Animal inhalin§f strongs Chloroform vapour. Inspiratory stridor. 



Inspiratory Stridor. — Tracing 29 shows the effect upon the blood 

 pressure of inspiratory stridor produced by the inhalation of strong 

 chloroform vapour. A fall occurred during each inspiration. 



In Tracing 30 the left vagus had been already cut. At 10 the 

 right vagus was being handled, which produced some fall of pressure. 

 At 1 1 this nerve was divided and immediately the pulse increased in 

 rate, the pressure rose and the respiratory curve became more marked. 

 Each dip in the tracing was accompanied by an inspiratory stridor, 



Tracing XXX. — 9/31. — Left vagpus already divided. 11 Right vagus cut. 12 Inspiratory stridor set 

 in evidently of a paralytic n,iture. 



evidently caused by the flapping together of the vocal cords, the muscles 

 of which had been paralyzed by division of the vagi. This result, how- 

 ever, is not a constant one on division of the vagi. Thus, either spasm 

 of the laryngeal muscles as shown in Tracing 29, or paralysis, as shown 

 in Tracing 41, may produce inspiratory stridor, and this stridor is shown 

 to have a marked effect on the pressure. The stridor due to spasm 

 disappears as the animal becomes more deeply anaesthetized ; that due 

 to paralysis does not so go away. 



I The Lancet, Vol. I. i8qo. 



