SUSPENDED ANIMATION. 187 



blood through the lungs, which appears to be the first of the 

 events leading to suffocation, seems to depend on the cessation 

 of the interchange of gases, as if blood charged with carbonic 

 acid could not pass freely through the pulmonary capillaries. 

 But the stagnation of blood in the pulmonary capillaries 

 would not, perhaps, be enough to stop entirely the circulation, 

 unless the action of the heart were also weakened. There- 

 fore, 2dly, the fatal result is probably due, in some measure, 

 to the enfeebled action of the right side of the heart, in conse- 

 quence of its overdistension by blood continually flowing into 

 it ; this flow, probably, being much increased by the powerful 

 but fruitless efforts continually made at inspiration (Eccles). 

 And 3dly, because of the obstruction at the right side of the 

 heart, there must be venous congestion in the medulla oblon- 

 gata and nervous centres : and this evil is augmented by the 

 left ventricle receiving and propelling none but venous blood. 

 Hence, slowness and disorder of the respiratory movements 

 and of the movements of the heart may be added. Under all 

 these conditions combined, the heart at length ceases to act ; 

 the cessation of its action being also in great measure, proba- 

 bly, brought about, 4thly, by the imperfect supply of oxyge- 

 nated blood to its muscular tissue. 



In some experiments performed by a committee appointed 

 by the Medico-Chirurgical Society to investigate the subject of 

 Suspended Animation, it was found that, in the dog, during 

 simple apnoaa, i. e., simple privation of air, as by plugging the 

 trachea, the average duration of the respiratory movements 

 after the animal had' been deprived of air, was 4 minutes 5 

 seconds ; the extremes being 3 minutes 30 seconds, and 4 

 minutes 40 seconds. The average duration of the heart's ac- 

 tion, on the other hand, was 7 minutes 11 seconds; the ex- 

 tremes being 6 minutes 40 seconds, and 7 minutes 45 seconds. 

 It would seem, therefore, that on an average, the heart's action 

 continues for 3 minutes 15 seconds after the animal has ceased 

 to make respiratory efforts. A very similar relation was ob- 

 served in the rabbit. Recovery never took place after the 

 heart's action had ceased. 



The results obtained by the committee on the subject of 

 drowning were very remarkable, especially in this respect, that 

 whereas an animal may recover, after simple deprivation of 

 air for nearly four minutes, yet, after submersion in water for 

 li minutes, recovery seems to be impossible. This remark- 

 able difference was found to be due, not to the mere submer- 

 sion, nor directly to the struggles of the animal, nor to depres- 

 sion of temperature, but to the two facts, that in drowning, a 

 free passage is allowed to air out of the lungs, and a free en- 



