Other illustrations of phenomena of disease from deficient elimination of a natural excretion are shown in instances where the product of respiration, called commonly carbonic acid, is not duly eliminated by the lungs.
Certain of these phenomena are most strikingly seen during conditions which lead to what is known as asphyxia. If, under any circumstances, the respiration be interferred with, so that a due quantity of air is not taken into the lung, or a due escape of air does not take place from the lung, as occurs through suffoca-. tion from hanging, drowning, immersion in a mephitic atmos phere, and the like, there is accumulation of the carbonic acid in the blood, and symptoms of danger and death from that cause. These symptoms are darkness of the face and surface of the body generally, coldness, convulsion, and insensibility. They are the acute symptoms of suppressed respiratory excretion.
In some instances the suppression of the respiratory excretion may be slower in character, and may give rise to symptoms very painful to bear and to witness, but not necessarily fatal, imme diately. These states are usually brought about from some defect in the mechanisms of the circulation and of the respiration. In the newly born it occasionally happens that there is an imperfect expansion of the air vesicles of the lungs, so that a portion of the lung structure is not brought into play. Thereupon there is diminished inspiration, which, if it do not prevent, from the first, the manifestation of life, leads to difficulty of respiration, cold ness of surface, and impaired nutrition, with the common risk of early death from respiratory failure. To this form of disease the term atelectasis has been applied.
In other instances the opening from the right to the left side of the heart, the foramen ovale, which naturally closes after birth, remains open, and the blood from the right auricle of the heart, which ought to go altogether into the right ventricle, escapes, in part, as venous blood into the left auricle, and in this state, un charged with oxygen, circulates through the body. Under these circumstances the body is rendered dark in color over all its sur face, cold and enfeebled, a diseased condition which has already been under our observation at page 136, where it is defined under the head cyanosis.
In persons who are subject to spasm of the minute bronchial tubes, persons who are often called asthmatic, the same dangers from imperfect elimination of the expiratory excretion often occur, and death from asphyxia would be easily induced but for the circumstance that the prostration produced by the seizure leads to relaxation of the constricted tubes, and so permits the air once more to enter the temporarily occluded lung.
I do not doubt that there are many other conditions in which a deficient excretion of the respiratory products leads to disease, and even to death, by natural process of poisoning, and I know that much remains here to be explored and explained. Under the title " Asphyxia commencing in the Blood," I have described in another place various conditions in which this kind of poison ing may occur. It is enough for me in the present place to state the few well-defined illustrations which have been supplied under this head of Asphyxia and Cyanosuria.