igoo-i.] Observations on Blood Pressure. 217 



Artificial respiration was stopped and the pressure fell slightly, but 

 natural respiration soon set in, and after that the animal g-radually 

 recovered, the pulse as usual becoming very fast during recovery. 

 This tracing shows then the good effect of artificial respiration 

 on the heart. The method might almost as properly be called 

 " artificial circulation " as " artificial respiration ; " which name would 

 constantly remind one that he was directly acting on the heart while 

 performing the movements of the method. 



The effect of Tracheotomy on the blood pressure is interesting. 

 Besides being useful in cases where some obstruction in the air passages 

 exists above the level of the wound thus made, the operation appears to 



Tracing XXXIII.— q/31. — Dog poisoned by Chloroform. Respiration stops. Artificial respiration 

 tried without avail. 17 Trachea opened and respiration commenced at once and remained. 



stimulate the respiration reflexly. In Tracing 33 the respiration had 

 ceased as a result of chloroform poisoning, while the pulse continued. 

 Artificial respiration had been performed, but no attempt at natural 

 respiration appeared. The tongue had been drawn out forcibh' and 

 repeatedly (Laborde's method), and the air passages were clear. 

 Tracheotomy was performed at 17, and at once the animal commenced 

 to breathe and soon recovered. 



Tracing 34 shows the same phenomena even better. Natural 

 respiration had stopped here for several minutes. The puncturing of 

 the trachea at 27 at once was succeeded by a gasp and rise in blood 



Tracing XXXIV. — 9/28. — Dog poisoned with Chloroform. Natural respiration stops for ten minutes ; 

 Artificial respiration being continued. 27 Trachea opened and artificial respiration continued as 

 before. 28 Natural respiration occurred and animal recovered. 



pressure as shown in the tracing, and the animal recovered. The air 

 passages were clear. The effect on the respiration here is evidently of 

 the nature of reflex stimulation. The same thing is seen often when 

 the surgeon is performing tracheotomy for any condition. As the 

 trachea is punctured a violent gasp occurs. In desperate cases of 



