240 RESPIRATION. 



3 minutes 30 seconds, and 4 minutes 40 seconds. The 

 average duration of the heart's action, on the other hand, 

 was 7 minutes 1 1 seconds ; the extremes 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 

 observed 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 depriva- 

 tion of air for nearly 4 minutes, yet, after submersion in 

 water for i% minutes, recovery appears to be impossible. 

 This remarkable difference was found to be due, not to 

 the mere submersion, nor directly to the struggles of the 

 animal, nor to depression of temperature, but to the two 

 facts, that-ill drowning, a free passage is allowed to air out 

 of the lungs, and a free entrance of water into them. In 

 proof of the correctness of this explanation, it was found 

 that when two dogs of the same size, one, however, having 

 his windpipe plugged, the other not, were submerged at 

 the same moment, and taken out after being under water 

 for 2 minutes, the former recovered on removal of the plug, 

 the latter did not. It is probably to the entrance of 

 water into the lungs that the speedy death in drowning is 

 mainly due. The results of post-mortem examination 

 strongly support this view. On examining the lungs of 

 animals deprived of air by plugging the trachea, they 

 were found simply congested ; but in the animals drowned, 

 not only was the congestion much more intense, accom- 

 panied with ecchyrnosed points on the surface and in the 

 substance of the lung, but the air-tubes were completely 

 choked up with a sanious foam, consisting of blood, water, 

 and mucus, churned up with the air in the lungs by the 

 respiratory efforts of the animal. The lung-substance, 



