But in one respect all fangs agree, and that is in their delicacy and fineness. Under the microscope, the stronger the lens the greater the degree of exquisite polish and sharpness revealed. To handle those of very young vipers is as difficult as it would be to handle fine needle-points of similar length. One can compare them with nothing else, except perhaps the fine thorns of the sweet briar, which are equally unmanageable, and, as compared with manufactured articles, equally exquisite.
Sir Samuel Baker describes the fangs (both functional and supplementary) of a puff adder which he found. His words, if not strictly scientific, are so graphic as to convey a true idea of these terrible weapons. The viper was five feet four inches long, and fifteen inches in girth in its largest part. The head was two and a half inches broad. Sir Samuel counted ‘eight teeth’ (fangs), and secured five of them, the two most prominent being nearly one inch long. ‘The poison fangs are artfully contrived, by some diabolical freak of nature, as pointed tubes, through which the poison is injected into the base of the wound inflicted. The extreme point of the fang is solid, and is so finely sharpened that beneath a powerful microscope it is perfectly smooth, although the point of the finest needle is rough!’[95] He describes the aperture in the fang as like a tiny slit cut in a quill.
This ‘slit’ is a very important feature in the fang, and is the cause of much trouble in deciding whether a bitten person has been poisoned or not. It is in reality a very small space near the point, where the involution of the fang is incomplete, that is, where it has remained unjoined. This is to permit the emission of the venom. It is not close to the point, which, as Sir S. Baker affirms, is solid. Being solid, it is stronger and sharper, penetrating the skin of the victim more easily, and making way for the venom which in viperine fangs then follows and escapes through the slit into the wound. By this we comprehend how a person may receive a puncture only, or a scratch with this extreme but solid point, but not deep enough for the poison to enter. The space between the lines at a in the next illustration shows where this slit in the fang is found. In the larger fangs it may be readily discerned with the naked eye: under a magnifying glass it is distinguishable in all. It is distinct in the fangs of the young Jararacas now before me, and extends nearly half-way up the fang in these.
The examples of fangs here given are all from nature, and as near to the exact size as it is possible to be in delineating objects of such exceeding fineness and delicacy. Excepting the Xenodon’s and the baby viper’s, the others belong to the Crotalidæ, whose fangs are mostly distinguishable by a slight double curve or flange. The viperine fang is a continuous curve (see f), but in the Crotalus the point curves very slightly back again and downwards.
For the Brazilian specimens, I am indebted to Dr. Arthur Stradling, who presented me with the snakes, out of whose jaws I myself procured them. In this Lachesis there were two fangs visible on one side, and only one on the other, viz. the functional pair, and one nearly ready to replace one of these. In addition to the pair were four reserve fangs hidden under the functional one on the right side. I say ‘under,’ because anatomically they were beneath, though locally above when the snake was in its natural position. All these five fangs I got from only one side, and in addition some others too small to represent. There may be yet more in the membranous capsule, as mine was a sadly unscientific search for them, and without any very powerful magnifier. Like Charas, I ‘grovelled’ for them! From a young Jararaca I also got out the functional and four or five supplementary fangs from one side, also an exceedingly small and short jaw-bone, leaving the other side undisturbed. Even the principal fang (d) is too fine to represent faithfully in printer’s ink; the others are to the naked eye and to the touch almost impalpable. When we reflect on the exquisite sharpness and finish of these minute weapons, and the fatal injury they are capable of inflicting, we are filled with awe and amazement at the virulence of the subtle fluid which oozes through that almost invisible aperture. The brother of this tiny African viper (f), when only a few hours old, struck a mouse, which was dead in less than one minute. The whole forty-six of them (p. 321) were born with the ‘murderous teeth’ in their vicious little jaws. The fang here represented was loose in its mouth. A pair of perfect functional fangs remained.
Fangs and some simple teeth from my specimens.
a. Functional fang and four supplementary fangs from Lachesis mutus (Brazil).
b. Rattlesnake fang.
c. Fang of young rattlesnake (Brazil).
d. Fang of young Jararaca (Brazil).
e. Pseudo ‘fang’ of Xenodon (Brazil).
f. Loose fang from the mouth of Vipera nasicornis, aged one week.
g. Portion of palate bone bearing four teeth, from Lachesis mutus (Brazil).
h. Two lower teeth from the same.
Picture to yourselves the intensity of that invisible molecule of venom, which could ooze through an equally invisible aperture in this last diminutive weapon, and be fatal to life in a minute of time! From the effects observed on victims, I am inclined to place these large African vipers amongst the most venomous of all serpents of their size.
It may be of interest to remark that the fang of the baby viper found loose in its mouth does not resemble those remaining, either in form or structure. That it cannot be a jaw tooth is evident from its size. Jaw and palate teeth there are, but discernible only to the touch, and under a magnifying glass. The fixed fang from the side on which I found this loose one, is a trifle shorter, and much finer than its fellow. In the loose one here given I can hardly discern any involution at all, but on touching it with the inky point of a fine needle, the stain shows it be hollow, and clearly so, at its base. In the two fixed fangs, however, the involution is so incomplete that, minute as they are, the point of a very fine needle can be drawn all down them without slipping off.