230 RESPIRATION. 



into the lungs that the speedy death in drowning is mainly 

 due. The results of post-mortem examination strongly sup- 

 port 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, accompanied with eechy- 

 mosed 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, too, appeared 

 to be saturated and sodden with water, which, stained 

 slightly with blood, poured out at any point where a section 

 was made. The lung thus sodden with water was heavy 

 (though it floated), doughy, pitted on pressure, and was 

 incapable of collapsing. It is not difficult to understand 

 how, by such infarction of the tubes, air is debarred 

 from reaching the pulmonary cells : indeed the inability 

 of the lungs to collapse on opening the chest is a proof 

 of the obstruction which the froth occupying the air-tubes 

 offers to the transit of air. The entire dependence of the 

 early fatal issue, in apnoea by drowning, upon the open 

 condition of the windpipe, and its results, was also 

 strikingly shown by the following experiment. A strong 

 dog had its windpipe plugged, and was then submerged in 

 water for four minutes ; in three-quarters of a minute after 

 its release it began to breathe, and in four minutes had fully 

 recovered. This experiment was repeated with similar results 

 on other dogs. When the entrance of water into the lungs, 

 and its drawing up with the air into the bronchial tubes by 

 means of the respiratory efforts, were diminished, as by 

 rendering the animal insensible by chloroform previously 

 to immersion, and thus depriving it of the power of making 

 violent respiratory efforts, it was found that it could bear 

 immersion for a longer period without dying than when not 

 thus rendered insensible. Probably to a like diminution 



