ASPHYXIA -ITS CAUSES. 389 



with their hydrogen, at the same time that carbonic acid is produced by 

 its union with their carbon. 



702. Along with the water thus extricated from the lungs, a certain 

 amount of organic matter is set free. - If the fluid be collected in ~a 

 closed vessel, and be exposed to warmth, a very evident putrid odour 

 is exhaled from it ; and if the expired air be made to pass through 

 sulphuric acid, that liquid is coloured red. Every one knows that the 

 breath itself possesses, occasionally in some persons, and constantly in 

 others, a foetid taint ; when this does not proceed from carious teeth, 

 ulceration in the air-passages or lungs, or other similar causes, it must 

 result from the excretion of the odorous matter, in combination with 

 watery vapour, from the pulmonary surface. That this is the true 

 account of it seems evident, from the analogous phenomenon of the 

 exhalation of turpentine, camphor, alcohol, and other odorous sub- 

 stances, which have been introduced into the venous system, either by 

 natural absorption, or by direct injection; and also from the sudden- 

 ness with which the odour manifests itself, when the digestive appa- 

 ratus is slightly disordered. 



5. Effects of Insufficiency , or Suspension, of the Aerating Process. 



703. The change which the Blood undergoes, by being brought into 

 relation with atmospheric air in the respiratory organs, is so important 

 to life, that the entire suspension of it inevitably produces a fatal ter- 

 mination, at no remote period ; and if it be insufficiently performed, 

 various disorders in the system are nearly sure to manifest themselves. 

 The state which is induced by the entire suspension of the aerating 

 process, is termed Asphyxia ; a word which literally means the absence 

 of pulse, and would be applicable therefore to the stoppage of the cir- 

 culation from any cause ; though it is usually employed to designate 

 the particular condition resulting from suspended respiration. Asphyxia 

 may be produced in aquatic animals, as well as in those which breathe air, 

 by cutting them off from the influence of the atmosphere ; for if a fish 

 be placed in water from which the air has been expelled by boiling, it is 

 precisely in the condition of an air-breathing animal placed in a vacuum, 

 since it has no power of obtaining oxygen by decomposing the water it 

 inhabits, and is entirely dependent for the aeration of its blood, upon 

 the air that is absorbed by the liquid. Agairi^ if a fish be placed in 

 water impregnated with carbonic acid, its death is nearly as instan- 

 taneous as that of an air-breathing animal immersed in an atmosphere 

 of that gas. 



704. Asphyxia may result from a great variety of causes. Thus there 

 may be a mechanical obstruction to the entrance of air through the 

 trachea ; as in hanging, strangulation, or drowning ; or as in occlusion 

 of the, aperture of the glottis, by oedema of its lips, or by the presence 

 of a foreign body in the larynx. Or, again, the passage may be perfectly 

 free, and yet no air may enter, in consequence of some obstacle to the 

 performance of the respiratory movements. This obstacle may be me- 

 chanical ; as when a quantity of earth has fallen round the body, in such a 

 manner as completely to prevent the distension of the chest and abdomen. 

 Or it may result (and this is a most frequent occurrence) from torpidity 



