K ASPHYXIA ITS PHENOMENA AND TREATMENT. 391 



o sides. Both are equally affected by the want of arterial blood in the 

 capillaries of their own substance ; but the right side suffers from over 

 distension, which produces a sort of paralysis of its muscular tissue ; 

 whilst the left side retains its contractility, but is not excited to coir^ 

 traction, for want of the stimulus of arterial blood in its cavities. 



707. In those warm-blooded animals which are not endowed with 

 any special provision for enabling them to sustain life during the pro- 

 longed suspension of the respiratory process, insensibility and loss of 

 voluntary power almost invariably supervene within a minute and a 

 half after the admission of air to the lungs has been entirely pre- 

 vented; though the respiratory efforts and convulsive actions, which 

 are dependent upon the medulla oblongata and spinal cord, may con- 

 tinue for a minute or two longer. The circulation generally comes to 

 a complete stand within ten minutes at farthest. The chief exceptions 

 are in the case of diving animals, which are provided with large arterial 

 and venous reservoirs, that serve to maintain the circulation during 

 a prolonged suspension of the respiratory process ; for the arterial 

 plexuses being ordinarily filled, they afford a supply of aerated blood 

 to the systemic capillaries, when other blood is wanting ; and the reser- 

 voirs connected with the venous system, which were previously empty, 

 receive this blood, and prevent it from exercising undue pressure on 

 the heart. To such an extent is this provision carried in some ani- 

 mals, that the Whale has been known to remain under water for an 

 hour. Another exception exists in the case of hybernating Mammals, 

 which are reduced for a time to the condition of cold-blooded animals, 

 and which can, like the latter, sustain a prolonged suspension of the 

 aerating process. And there is reason to believe that, in the state of 

 Syncope or fainting, in which the circulation is already reduced to a 

 very low amount, in consequence of a partial failure in the heart's 

 power, all the functions of the body being nearly suspended, and the 

 demand for aeration being consequently very small, the respiration 

 may be suspended for a long period, even in the Human subject, with- 

 out fatal results. Thus more than one case has been credibly recorded, 

 in which recovery has taken place after complete submersion for more 

 than three quarters of an hour ; and it is probable that, in these in- 

 stances, a state of Syncope came on at the moment of immersion, 

 through the influence of mental emotion, or of concussion of the brain. 

 708. In the restoration of an animal from the state of Asphyxia, 

 it is above all things of importance to renew the air in the lungs ; for 

 in this way the blood in the pulmonary capillaries will be aerated, the 

 capillary circulation will be re-established, the right side of the heart 

 will be relieved of its excessive load of venous blood, and the left side 

 will receive the stimulus of a fresh supply of arterial blood ; so that, 

 if its movements have not ceased altogether, it may be speedily restored 

 to due activity. At the same time, the temperature of the body should 

 be kept up by artificial warmth ; and the circulation in the skin should 

 be excited by friction. Where no other means are* at hand for intro- 

 ducing pure air into the lungs (of which means the application of gal- 

 vanism along the course of the phrenic nerve, so as to produce contrac- 

 tion of the diaphragm, will probably be the most effectual), the object may 



