An inaugural essay on the effects produced by air upon living animals : submitted to the examination of the Revd. John Andrews, D.D. Provost, (pro tempore) the trustees, and medical faculty of the University of Pennsylvania, for the degree of doctor of medicine, on the 5th day of June 1805 / by Joseph Hartshorne, of Alexandria, in the District of Columbia.
- Hartshorne, Joseph, 1779-1850.
- Date:
- 1805
Licence: Public Domain Mark
Credit: An inaugural essay on the effects produced by air upon living animals : submitted to the examination of the Revd. John Andrews, D.D. Provost, (pro tempore) the trustees, and medical faculty of the University of Pennsylvania, for the degree of doctor of medicine, on the 5th day of June 1805 / by Joseph Hartshorne, of Alexandria, in the District of Columbia. Source: Wellcome Collection.
Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)
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![fluid: and the lungs which, according to the older physiolo- gists, were destined to fan and cool the blood, were now con- sidered as the focus from which the whole system was supplied with heat. Nearly a century elapsed before any further progress was made in investigating the properties of atmospheric air. That the atmosphere was a compound, and that during respiration its constituent parts were separated from each other, was an opinion adopted by several respectable writers. But it was a doctrine by no means generally received. It was by some considered merely as an hypothesis, and entirely destitute of proof. This class of physiologists, among whom we find the learned and indefatigable Haller, considered respiration as no- thing more than an excretory process. They supposed that something was discharged from the blood in its passage through the lungs, which if retained would he injurious to the system. In the year ] 756, Doctor Joseph Black made the first suc- cessful attempt to ascertain the changes produced in air by respiration. This able experimentalist examined with great care the gas silvestre of Van Helmont. He found that this gas was generated in large quantities by fermentation and combustion, that it possessed a strong attraction for lime and caustic pot-ash, and that its union with these substances ren- dered them mild, and capable of effervescing with acids. Hales had shewn, that breathing through pieces of cloth dipped in an alcaline solution made the air last longer for the purposes of life. This experiment induced Doctor Black to suspect, that fixed air was discharged from the lungs during respiration. By repeating the experiment of Hales it was proven, that caustic pot-ash was rendered mild by the expired air; and on breathing through lime water, the presence of fix- ed air was evinced by the precipitation of the carbonate of lime. In this manner the analogy between respiration and combustion, first observed by Boyle and Mayow, was render- ed very striking by the experiments of Black. We know](https://iiif.wellcomecollection.org/image/b21127128_0017.jp2/full/800%2C/0/default.jpg)
