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.

  • Joseph Hartshorne
Date:
1805
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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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    A few days afterwards I immersed two fresh eggs in the same vessel with the same quantity of common air. After re- maining ten hours at the heat of 100° they were taken out, and one hundred parts of the air were examined as in the last ex- periment, by leaving it twenty-four hours in contact with phos- phorus. At the end of that time nineteen parts of the air were absorbed. From this it appeared, that one third of the oxyge- nous gas contained in the vessel was consumed by the eggs. From these experiments it is evident, that an egg during in- cubation consumes more oxygen than a fresh egg. On exami- ning the air contained in fresh eggs I found, that it consisted of, about one part carbonic acid gas, from five to six parts oxygen gas, and from 93 to 94 parts azotic gas. The quantity of oxy- gen increases with the increase of vital action in the chick, as will appear by the following statement. On the 6th day of incubation the air of the egg contained 8 per cent oxygen, ]2th 10 per cent. H-th 13 percent. Does the egg during incubation possess the power of generating heat f « Having taken some eggs, says John Hunter, when the f« chick was about three parts formed, I broke a hole ia the « shell, and introducing the ball of a thermometer, found that the quicksilver rose to 99 \. In some that were addled I found the heat not so high by two degrees ; so that the life « in the living egg assisted in some degree to support its heat. With a view of ascertaining, whether this power of genera- ting heat be proportioned to the degree of vital action, I made the following experiments. A thermometer was introduced into an egg which had been six hours under the hen. The mercury rose to 97°, and retained that temperature for nearly three minutes, when it fell to 96°.