An experimental inquiry into the properties of carbonic acid gas or fixed air : its mode of operation, use in diseases, and most effectual method of relieving animals affected by it ; being an inaugural thesis, submitted to the examination of the Rev. John Ewing, S.T.P. provost ; the Trustees and medical faculty of the University of Pennsylvania, on the 12th day of May, 1797 ; for the degree of Doctor of Medicine / by Joseph Johnson, of Charleston, (S.C.) member of the Chemical, and honorary member of the Philadelphia Medical Society.

Joseph Johnson

Date:: 1797

Credit: An experimental inquiry into the properties of carbonic acid gas or fixed air : its mode of operation, use in diseases, and most effectual method of relieving animals affected by it ; being an inaugural thesis, submitted to the examination of the Rev. John Ewing, S.T.P. provost ; the Trustees and medical faculty of the University of Pennsylvania, on the 12th day of May, 1797 ; for the degree of Doctor of Medicine / by Joseph Johnson, of Charleston, (S.C.) member of the Chemical, and honorary member of the Philadelphia Medical Society. 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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To difprove thefe opinions, it will only be necefTary to refer to the comparative experiments of Dr. W. Bache, as publifhed in his Inaugural Differtation, and to thofe of Dr. Beddoes, in his Differtation on Factitious Airs. Dr. Bache found that animals in an artificial atmofphere of oxigene and carbonic airs, expired in 10 or 15 minutes; while others, equal apparently in every refpect, lived in the fame quantity, by meafurement, of atmofpheric air for the fpace of an hour without much inconvenience. Dr. Beddoes found that animals of the fame fpecies, of the fame litter, and apparently of the fame vigour ; if immerfed in carbonic acid, died in 1 1-2 minute, but in hydro- gene not till 22 minutes. From this we would conclude, that carbonic acid acts by an inherent power ; while azote and hydrogene act fnnply by preventing the influence of oxigene from coming in contact with the lungs ; for the length of time which life continues, when the animal is expofed to thefe two gafes fimply, is about the fame with its duration when the animal is immerfed in water. Mr. Coleman, to fupport his favorite idea of collapfe, aflerts, that no more of the noxious air enters the lungs during expofure to it, than of water, in thofe deflroyed by drowning ; but this affertion has likewife been difproved by an ingenious experiment of Dr. Bache. He introduced one end of a fyphon into a receiver filled with carbonic acid, the other end of which was fixed, by a bladder and drawing-firing, to the head of a dog : he obferved the water in the receiver over which the air was collected, to rife and fall alternately as the animal refpired. Mr. Coleman's explanation therefore of its effects, by fuppofing the carbonic acid to irritate the epiglottis, fo as to make it clofe and prevent the • entrance of this gas, while the air prCvioufly in the lungs is preiTed out by the different exertions, and a compleat collapfe takes place, being the immediate caufe of death ; muff, be wholly unfounded*

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