The anaesthetic effects of nitrous oxide & oxygen : when administered at ordinary atmospheric pressures with remarks on 800 cases / by Frederic Hewitt.

  • Hewitt, Frederic W. (Frederic William), Sir, 1857-1916.
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: The anaesthetic effects of nitrous oxide & oxygen : when administered at ordinary atmospheric pressures with remarks on 800 cases / by Frederic Hewitt. Source: Wellcome Collection.

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    not nearly so satisfactory as that adopted later, viz., commencing with a small percentage of oxygen and gradually increasing it. I also found that although this apparatus answered much better than all its predecessors, it yet allowed rather too much oxygen to come through as each hole was turned on. By a series of experiments I found, for example, that when five holes were open, as much as 13 per cent, of oxygen was breathed. Series 13 (162 Gases). The apparatus* used in this, the last series, differs only from that just described in that its oxygen holes are about one-half the size. This slight alteration has proved a very important one. The accompanying drawings show the apparatus with which the cases have been conducted. Two india-rubber bags are employed: one for nitrous oxide, the other for oxygen (fig. 1, 0)i These, which are fed from cylinders worked by the foot, are attached to two metal tubes T' and T. Where the tubes join there is an arrangement by which oxygen may be added to the current of nitrous oxide to the desired extent. Above this regulating arrangement with * Messrs. Barth &. Go., of Poland St., Oxford St., who have most patiently constructed various forms of apparatus for me, are the sole makers of that which I now use.