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"Editor refuses to publish letter from John Snow"

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(25 May 1839): 352

PDFs courtesy of Elsevier, via Health Sciences Center Library, Emory University. Included are M. H.'s "Note on respiration and asphyxia," Lancet 1 (4 May 1839): 240, and Wakely's snub accompanying a refusal to publish Snow's response to M. H.

From the Editor of the Lancet:

To Correspondents.

. . . . . . . [five editorial comments, unrelated to Snow, not included]

The remarks of Mr. John Snow on a recent communication from M. H., on the physiology of respiration, have been received. We cannot help thinking that Mr. Snow might better employ himself in producing something, than in criticising the productions of others.

. . . . . . [two additional editorial comments, also unrelated to Snow, not included]

[The contribution from M. H. that appeared in Lancet 2 (4 May 1839): 240 is reproduced below:]

Note on respiration and asphyxia.

The excitors of inspiration are the trifacial, the pneumogastric, and the spinal nerves. None of these can be affected in utero; for the excitant of the first and third is the cool atmosphere which is excluded until the fœtus is born; and the excitant of the second is the evolved carbonic acid, which is not evolved until atmospheric air has been introduced into the air-tubes and air-cells.

There is much to admire in all this, which passes unnoticed by the superficial observer. The pneumogastric would exist in vain if inspiration were not first excited by another excitor, placed on the surface of the animal body. Evolved carbonic acid, the future excitant of respiration, is not evolved unless the atmospheric air be first brought into contact, as it were, with the venous blood, a fine membrane only being interposed.--(Dr. Stevens, "Phil. Trans." for 1835.) But first by the contact of the cool atmosphere with the trifacial and spinal nerves, and ever after by the agency of atmospheric air, but especially of its oxygen, in contact with venous blood, and the consequent evolution of carbonic acid, the future excitant of inspiration, respiration is begun and continued.

The fœtus in utero makes no effort to breathe, because neither the trifacial nor the pneumogastric is excited. The hybernant animal breathes little for the same or similar reasons. But dash cold water on the surface, or excite the evolution of carbonic acid, by augmenting the circulation by muscular effort, and respiration will be immediately and proportionately excited.

During asphyxia, whether from the exclusion of atmospheric air, or from the presence of carbonic acid, the acts of respiration become violent, anormal, and convulsive,--convulsive gaspings, with efforts of expiration, and, finally, general convulsions frequently closing the scene. Asphyxia is, in a word, nearly allied to epilepsy.


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