In another paper read before the Royal Society in 1726, also anterior to Fontana, on the ‘Fangs of the Rattlesnake,’ the writer, Captain Hall, describes the dissection, which was under the direction of Sir Hans Sloane; and ‘then the Muscles that raise the poisonous Fangs appear.’ This anatomist also found reserve fangs. ‘Putting by this Membrane, the fatal Fangs appear, which on first View seemed only one on each Side, till searching further there appeared four more. The first and largest is fixed in a Bone;’ four others were loose in the membrane.[103]
Several of the old authors quoted in the chapter on Rattlesnake History of the Seventeenth Century were quite aware of the action of the ‘Springing Teeth,’ ‘Master Teeth,’ or ‘Canine Teeth,’ as the fangs were variously called; and Lawson, 1707, describes ‘the Teeth which poison are two on each side of the Upper Jaws. These are bent like a Sickle, and hang loose as if by a Joint.’ Fontana’s observations were possibly of greater scientific importance, otherwise it is singular that his equally thoughtful predecessors, from whom he no doubt culled much important information, should have been overlooked.
In these viperine fangs there is an analogy between the vipers and the lophius, a fish with moveable teeth; only in the fish, as Owen tells us, the action is not volitional,—the teeth bend back to admit food, and then by elastic muscles spring up again to retain it.
The true nature of the reserve fangs was surmised by Mr. John Bartram, who in 1734 wrote from German Town, in the American colonies, to a F.R.S., ‘On a Cluster of Small Teeth at the Root of each Fang or Great Tooth.’[104] He had a rattlesnake, ‘now a Rarity near our Settlements,’ and dissected it, when he ‘found in the Head what has not been observed before by any that I can remember; i.e. a Cluster of Teeth on each side of the Upper Jaw at the Root of the Great Fangs through which the Poison is ejected. In the same Case that the two main Teeth were sheathed in, lay four others at the Root of each Tooth in a Cluster of the same Shape and Figure as the great ones, and I am apt to think for the same Use and Purposes, if by an Accident the main Teeth happen to be broken. May not these be placed to supply a Defect successively, for the Support of this Creature?’
Mr. Bartram was singularly correct in his diffidently-offered surmises; nor is it likely that in such a remote district as German Town then was, he had ready access to foreign publications, or would have claimed originality had he been cognisant of the work of M. Moyse Charas, New Experiments upon Vipers, translated from the original French in 1673. Charas, after describing the ‘Great Teeth,’ refers to the ‘smaller teeth’ (reserve fangs) ‘that are there in a Nursery, and are, if we may say so, in expectation to serve instead of the many Teeth, whether these come to fail of their force, or fall out of themselves.’ The author, to add weight to conclusions evidently originating from personal investigations, tells us that he had ‘taken Pains to grovel with a good deal of Patience in the Gums of innumerable Vipers.’
The Italian Redi, even prior to Charas, had also ‘grovelled’ in the gums of Vipers, and observed the canal or slit in the fang, ‘si fendono per lo lungo dalla radice alla punta,’ and that these canaliculated teeth in the moveable jaws (ossi mobili) were for the conveyance of the venom.[105]
Thus, one hundred years prior to the work of Fontana, the structure of the viperine jaw was understood and described by several—we may almost say many—anatomists, to whom let due honour be rendered for their individual and independent researches; from all of which Fontana had doubtless benefited.
And so from numerous sources we might go on culling and quoting; Philosophical Transactions of France, Florence, Germany, and America, as well as of England, showing us that little by little the scientific workers examine, compare, correspond, till out of their life’s labours a fact is established that may be printed and learned in six lines, but which—as is well worth remembering—often represents the brain and eyes and time of ages of scientists.
Next to engage attention was the structure of the fang and the ‘involution’ described in the last chapter. A paper on this subject by Thos. Smith, Esq., F.R.S., was read before the Royal Society in 1818. Mr. Smith claims to have been the first to observe this involution as being altogether different from the perforation of the pulp originally supposed to be the case. He first noticed the slit in a cobra’s fang (he being in India), and afterwards in a Hydrus (sea snake), and it led him to further investigations. With a microscope the slit was perceptible in a rattlesnake fang (which was also observed by the present writer before reading this account).
One more paper in the Philosophical Transactions on this subject must be commended to the interested student. It is the one already quoted (p. 363), ‘On the Succession of Poison Fangs,’ by Charles Tombes, M.A., vol. clxvi. p. 470, 1876. In this paper is presented the result of all the most recent investigations, enriched by still deeper researches, but of too scientific a character to be introduced in this simple narrative of the progress of ophiology. We may, however, say that Mr. Tombes finds the character or function of succession differs in the vipers from that of the venomous colubrines; and this, as the construction of their fangs and maxillary jaw differs, is what we might look for.