SUFFOCATION FROM WANT OF RESPIRATION. 
287 
lity, its actions first become irregular, producing violent con¬ 
vulsive movements, and at last cease altogether, the animal 
becoming completely insensible. In this condition, which is 
termed Asphyxia ,, the pulmonary arteries, the right side of the 
heart, and the large veins which empty themselves into it, are 
gorged with dark blood ; whilst the pulmonary veins, the left 
side of the heart, and the arteries of the system, are compara¬ 
tively empty. Hence the action of the right side of the heart 
comes to an end, through a loss of power in its walls, occa¬ 
sioned by their being over-distended; whilst that of the left 
side ceases for want of the stimulus of the contact of blood, 
by which the muscular fibre is excited. If this state be 
allowed to continue, death is the consequence; but if the 
carbonic acid in the lungs be replaced by pure air, the flow of 
blood through their capillaries recommences,—the right side 
of the heart is unloaded and begins to act again,—arterial 
blood is sent to the left side, and excites it to renewed motion, 
—and the same being propelled by it to all parts of the body, 
their several functions are restored, the nervous system re¬ 
covers its power of acting, and all goes on as before. These 
changes occur in exactly the same manner when a warm¬ 
blooded animal is made to breathe nitrogen or hydrogen ; 
since these gases do not perform that which it is the office of 
oxygen to effect,—the removal of carbon from the system, in 
the form of carbonic acid. And they also take place in a 
perfectly pure atmosphere, when the individual is prevented 
from receiving it into its lungs by an obstruction to its passage 
through the windpipe, such as that produced by hanging, 
strangulation, drowning, &c. For the air in the lungs, not 
being renewed, speedily becomes charged with carbonic 
acid, to an extent that checks the circulation through their 
capillaries; and all the consequences of this follow as 
before. 
339. The most efficient remedy in all such cases is evidently 
that suggested by the facts stated in the last paragraph,— 
the renewal of the air in the lungs. But with this, other 
means should be combined; and the general directions 1 
of Dr. Marshall Hall, with the method of producing artificial 
1 The instructions, though specially intended for the resuscitation of 
persons apparently drowned, are applicable with slight modification to 
other forms of Asphyxia. 
