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.