1865.] restoring the Life oj 'Warm-blooded Animals ,fyc. 361 



Narcotism was again carried on to the same extremity, with recovery on 

 inflation ; and this was repeated once more with the same result. But in 

 this experiment, although, to appearance, animal action was entirely sus- 

 pended, a minute examination of the heart, through an opening in the skin 

 sufficiently large to allow the mouth of the stethoscope to rest on the ribs, 

 but not to injure either them or the intercostal muscles, proved that there 

 was still sufficient action of the heart to produce a faint first or systolic 

 sound. 



Cessation of the heart during artificial respiration. Order of cessation. 

 These experiments by inflation were modified. So soon as the animal 

 ceased to exhibit evidence of life, the artificial respiration was set up, the 

 chest-wall was removed, and the effects of the artificial respiration on the 

 heart were observed. In every case where the operation was performed 

 within five minutes the heart was discovered pulsating. The action was 

 uniformly best marked in the right auricle, next in the right ventricle, 

 next in the left auricle, and next in the left ventricle. Contraction remained 

 longest also in the same order. But it was observed uniformly that the 

 contraction of the right ventricle never sufficed to fill the pulmonary artery 

 with blood so as to reestablish the pulmonic circuit. 



Effect of inverting the body. In one case the animal was suspended 

 with the head downwards while the right ventricle was contracting vigo- 

 rously. In this case blood passed into the pulmonary artery and faintly 

 coloured the surface of the lung, which was previously pale ; but the pul- 

 monic circuit was not reestablished, and after death the capillaries were 

 found to be obstructed mechanically from coalescence of the blood- 

 corpuscles. 



Effects of artificial inflation with air raised in temperature. These ex- 

 periments with the chest laid open were varied by the employment of air 

 at different temperatures. The evidence was clear that when the contrac- 

 tions of the heart were failing, an increase in the temperature of the air 

 to 140 Fahr. caused a more vigorous action, which often lasted from five to 

 ten minutes. 



Effect of exposure to the air in exciting cardiac action. To determine 

 whether the act of insufflation of air at a mean temperature of 60 was 

 sufficient of itself to set up contraction of the heart, two animals were de- 

 stroyed with chloroform and allowed to rest fifteen minutes. Then in one 

 animal artificial respiration with air at 60 was employed for five minutes, 

 and the hearts of both animals were immediately exposed to view. There 

 was no action in either case at first ; but after exposure to the air for a few 

 minutes the right auricle in both hearts commenced to contract, and the 

 ventricles followed. But the action was in no way more determinate in the 

 animal that was receiving air by inflation than in the other animal. I 

 notice this point particularly, because some experimentalists, who have made 

 but one or two observations, on seeing the heart pulsate during artificial 

 respiration, have conceived that the phenomenon was due solely to the in- 



