Specification of William Edward Gedge : syringe for subcutaneous extractions and injections.

  • Gedge, William Edward.
Date:
1870
Catalogue details

Licence: Public Domain Mark

Credit: Specification of William Edward Gedge : syringe for subcutaneous extractions and injections. Source: Wellcome Collection.

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    G edge's Improved Syringe, _ which are fixed at P and G two short tubes or cannula pieces, each provided with a cock, and having an inner screw thread for the fixing of a trocar or of an ordinary cannula. For subcutaneous extractions the end of the cannula piece P is fitted with a trocar of the required length (on reference to Pig. 2 it will he 5 observed that the trocar is pierced with several holes to avoid obstruction), and after its introduction into the part to be explored it is only necessary to create a vacuum in the syringe to draw out the matter sought for. In case of continuous punction or tapping another piece of ordinary 10 cannula will be added to that G, and when the barrel or chamber of the syringe is filled with matter to be ejected the cock of the cannula P wifi be closed, that of the cannula G opened, and the contents of the syringe will be forced out. This operation may be repeated as many times as may be required without the necessity of displacing the apparatus. 15 To transform this extractor into an injector it will only be necessary to fit it with an ordinary trocar cannula, that is to say, one pierced at the end with but a single hole (see Pig. 3), and to introduce this cannula into the part to be injected, care being had to keep the cock P closed, the cannula G will be made to dip into the liquid to be injected, the 20 cock G will be opened and the liquid sucked into the syringe, then the cock G will be closed, that P opened, the liquid injected, and so on. When it is desired to use this instrument for local ancesthesis an ordinary cannula will he fitted to P, care being taken that this cannula 25 is pierced with as small a hole as possible. The syringe will be filled with ether, and the time indispensable for emptying the syringe on to the parts to he treated will be sufficient to produce complete anoesthesis. The piston rod of this syringe may be graduated by means of a screw thread and a nut E to regulate its stroke, and thereby to regulate the 30 dosing whether for extraction or injection. Ey a special arrangement of the piston rod the vacuum may be maintained in the pump barrel so long that the liquid to be sucked in shall enter it by the simple effect of the vacuum. The vacuum being formed by the simple traction of the piston rod the question is how to preserve it, and for this purpose a 35 notch is made in the lower .part of the piston rod, and a projection on that part of the cover of the pump barrel which forms socket; the rod