Researches upon the venom of the rattlesnake : with an investigation of the anatomy and physiology of the organs concerned / by S. Weir Mitchell.

  • Mitchell, S. Weir (Silas Weir), 1829-1914.
Date:
[1860]
Catalogue details

Licence: Public Domain Mark

Credit: Researches upon the venom of the rattlesnake : with an investigation of the anatomy and physiology of the organs concerned / by S. Weir Mitchell. 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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    although it runs through the centre of the booth, ia really on the outside of the t..oth. The bending of the dentine beyond it. begins a little beyond the base of the tooth, where the poison duct rests in a Blight groove, or longitudinal indenta- tion, on the convex side of the fang; as it proceeds, it sinks deeper into the aul> stance of the tooth, and the sides of the groove meet and coalesce, so that the trace of the inflected fold ceases, in some species, to be perceptible to the naked eye, and the tang appears, as it is commonly described to be, perforated by the duct of the poison gland. The tooth fang, in the Rattlesnake, has a peculiar double curve. The lower curve is large, and has an anterior convexity; the upper involves only two or three lines of the length of the tooth from the point down, and is nearly straight, or presents ;i slight concavity anteriorly. The whole length of the fang, from point to base, was /„ of an inch in a snake, four feet two inches long. One-tenth of an inch below the point in this tooth, the poison canal opened on the anterior, or con- vex surface of the fang. Above this, the fang was solid ; as the true pulp cavity terminated some distance lower down. The point of this singular weapon is brittle, but of an exquisite fineness. The tooth thus described, is firmly anchylosed to the submaxillary bone, its base being luted to the portion of bone around its side and anterior aspect. Posteriorly, the bone possesses a hollow, in which is lodged the tooth sac. In the open mouth of this alveolar process, within the mucous mem- brane, and upon the pterygoid bone, lie one behind and below another, the reserve fange, each smaller than the one in front, and less and less developed, until the situation of the last which is visible, is marked by a minute papilla alone. I have counted from eight to ten of these on each side. A very good account of their gradual development has been given by W. J. Burnett.1 The details do not directly concern us here. When the fang is lost by a natural process, it is replaced within a few days. When violently displaced, several weeks sometimes elapse before the next fang is fixed firmly enough to be useful to the snake. If the functional fang be lost or shed, the next tooth gradually assumes its position, but of the mode in which the communication is re-established between the poison duct and the fissure of the lower part and front of the new tooth, we have had no correct knowledge until a recent period. Burnett states, that the original tooth follicle appears to him to become the poison gland or sac. He then goes on to support this view briefly, still speaking of the poison gland as possibly accompanying the tooth in its forward movement. Dr. Burnett must have made this statement under a misconception, as it is well known there is no poison sac or gland at the base of the fang, or in immediate connection with it. More recently, the subject of the development of the fangs and the mode in which the fixed fang is replaced, when shed or broken, have been carefully studied by my friend, Dr. Christopher Johnston, of Baltimore, whose skill as an observer, 1 W. J. Burnett, M. D., Boston Nat. Hist. Soc, vol. iv. p. 311-323.