Fig. 285.—Quinlan Paraffin Heater.
Downie winds fine platinum wire about the needle through which he passes the current from a storage battery to keep the needle hot, yet such an arrangement is obviously difficult of manipulation, and when paraffins of high melting points are employed it is quite likely that a plug is formed in the exposed point of the needle.
Karewski has introduced a syringe having a jacket through which hot water is allowed to circulate, while similar instruments have been originated by Pflugh and De Cazeneuve. None of these overcome the difficulty in question.
Viollet went even further by inventing a syringe surrounded with a coil of resistance wire, heated by an electrical current, and Delangre, Ewald, and Moszkowicz use special thermophorm sleeves over the syringe proper; all, however, offering the same objection in the exposure of a part of the needle in which temperature of the liquid must necessarily be lowered, or be low enough to cause plugging, the very fault for which all these modifications have incidentally been urged, as the greater amount of paraffin in the syringe itself is as a rule large enough to retain sufficient heat to permit of its ejection, if the injection is made as expeditiously as possible.
The objection of the setting of the paraffin in the barrel of the syringe has never hampered any operator, the difficulty in these instances having been entirely due to the obstruction offered its ejection by the threadlike plug obstructing the metal cannula before it; the barrel, being glass, retains its temperature more readily than the thin metal needle, hence the difficulty.
That all prothetic preparation of the nature in hand should be placed in the barrel of the instrument in liquid form is essential, in that the syringe is thus filled to its required height evenly, and devoid of air spaces, yet in the light of the best and most successful results the mass should be allowed to cool and be ejected in semisolid state from a specially constructed instrument, to be described later.
With such method it is impossible to have an occlusion of the needle at any time, and the objection of sudden outbursts of unknown and undesirable quantities of the mass is entirely overcome.
15. Absorption or Disintegration of the Paraffin.—The question of the ultimate disposition of paraffin, injected subcutaneously for any purpose, has been an extensive one in which many operators have taken part.
Gersuny at first claimed an encapsulation for the injected mass of vaselin, which he states was not taken up by the lymphatics, but remained in situ as an inert, nonirritating body. Shortly after it was shown that the encapsulated mass soon became ramified by newly formed, fine bands of connective tissue, which developed more and more in the part until the entire mass had become displaced by this tissue with an eventual consistency of cartilage.