14. Mode of Condensing and Preserving Vegetable Substances for Ships’ Provision, &c.
15. Rewards for the Discovery of Quinia, and for Lithotrity.
16. Upon the Gaseous Exhalations of the Skin.
From the experiments of M. Collard de Martigny, he deduces,
i. That a gaseous exhalation really takes place from the skin.
ii. This exhalation is not morbid: it is observable in health.
iii. It is composed of carbonic acid and azote, in very variable proportions. The following experiment was frequently made. The bubbles of air which are disengaged from the skin were received into a funnel, the top of which was closed: they were then passed into a graduated tube, and agitated with a solution of potash. The height to which the solution rose in the tube indicated the quantities of carbonic acid that had been absorbed. All these operations were made at the same temperature and pressure. Neither hydrogen nor oxygen gas were discovered in this air.
iv. It does occur continually; but very often we may vainly attempt to discover it, which has been the cause of error in the results of Priestley, Fontana and Fourcroy. It is especially suspended after exercise long continued in the middle of the day, or immediately after taking an abundant meal. Sometimes it is suspended without any apparent cause.
v. The quantity also is very variable; but it was observed to be constantly in an inverse ratio to the cutaneous absorption.
vi. The proportions of the two gases vary very much, and sometimes the exhaled gas consists almost entirely of azote: in other instances the predominance of carbonic acid is so great that it appears to be the only product.—Med. Rep., N. S. v. 75.