| Parts. | |
| Nitrogen | 80 |
| Oxygen | 18 |
| Carbonic acid | 2 |
about three parts of the oxygen were absorbed, whilst about twelve parts of carbonic acid were exhaled, the nitrogen being little altered, or even receiving some small addition. The quantity of inspired oxygen which disappeared varied in different experiments, probably depending on the depths of the inspiration, and the duration between it and the following expiration—the time, in fact, during which it was retained in the lungs. The smallest quantity which disappeared was one-twelfth; the largest, one-sixth. The moisture (water) exhaled, he found to be about three drachms in an hour.
These experiments, for the particulars of which we must refer to the book itself, contain a calculation of the extent of surface of the body, which he estimates at about two thousand seven hundred square inches—that is, about thirty-eight times that of the hand and wrist, on which he experimented. Thus, if we multiply any of the results he obtained by thirty-eight, we shall obtain some idea of the prodigious power of this wonderful organ, and of the vast influence which its various conditions must exert on the whole animal economy. The whole of the experiments in the paper are just as interesting as ever, and would, we are well persuaded, be found amply to repay further investigation.
They exemplify in every line his clearness of thought, and his care in deducing no other conclusion from the premises than that which they logically justify. The observations which he has annexed to his paper also are just, and of great practical value; they discuss the bearing that the whole has to the relation which exists between the skin and lungs, and the influence of this on the causes of that fell destroyer, popularly known under the title of Consumption.
They are a portion of that investigation of relation between various organs, on which anything like the formation of a definite and practical science must ultimately depend. We shall endeavour, in the sequel, to explain the ulterior consequences which necessarily arise out of such considerations, when they are duly followed out. We shall endeavour to point out the share they had, in conjunction with other considerations, in leading to those beautiful and simple principles which Mr. Abernethy was led more especially to advocate; and show how far he went, as describing the starting point of those who have endeavoured at a fuller development of the consequences of his views.
He remarks, justly enough, on the determination to the lungs consequent on the repression of the surface, and the necessary additional duty thrown on those important organs engaged in a common function with the skin, where the duty of the latter is not performed; and on the elements thus supplied for disease, especially in persons of restricted chest; relations, be it remembered, which exist between the various other organs of the economy, and which exemplify in a single case truly, what has been, we trust, since shown in regard to organs generally; how the organ, which may be the seat of the disease, may not be the seat of the original cause, but really a secondarily affected organ—a hint which, when followed out, is of immense practical importance.
The skin is by no means the only organ which has a community of function with the lungs, or through which these important parts become affected; but if this be so, and diseases of the lungs be treated as an integral thing, it requires no great penetration to see how diseases so handled must be incurable; since the real cause may never be ministered to.
Again, if a case should be successfully treated, by means which afford all possible relief to the lungs, whilst the primarily affected organ is also properly treated, it by no means follows that the treatment should be the same in every case; for the primarily affected organ may be different in different cases. There is, in fact, no organ of the body which, when subjected to disordering influences, may not secondarily affect the lungs.
The liver is especially apt to affect them. It is engaged, like the lungs, in throwing off large quantities of carbon or charcoal from the system, and has been not very improperly termed the "abdominal lung." It is constantly also sending through the medium of the heart a large quantity of blood to the lungs. Now, if this blood have not the proper quantity of carbon extracted from it by the liver, or if even the blood be excessive in quantity, why the lungs must have more to do; and many diseased lungs have been produced in this manner in cases where the chest has been well formed.