The renewal of poison fangs is another subject of interest to ophiologists: how the next supplementary fang becomes fixed, _anchylosed_ to the jaw-bone; and how and when the connection with the poison duct is completed. Mr. Tombes, in a paper read before the Royal Society in 1875, describes a ‘scaffolding’ of bone thrown out to meet and grasp the new fang, to ‘interdigitate and fix it in its place; this soft bone rapidly developing and hardening.’ Sufficiently marvellous is the functional fang in itself; the insertion of the venom, a mode of subcutaneous injection invented long before the doctors thought of it. ‘A most perfect hypodermic syringe,’ Huxley calls it. Suddenly the hypodermic syringe is removed, say by accident, by force, or by gradual decay, and all connection with the gland is cut off; yet within a given period a second, a third, an unlimited number in turn replace it: the connection is restored and the hypodermic syringe is ready for action again. How the new one is brought into relation with the poison duct has afforded much speculation, and in the American scientific journals, as well as those of Europe, papers on this subject appear from time to time. Dr. Weir Mitchell of Philadelphia affirms that when the fang is lost by natural process it is replaced in a few days: when by violence, several weeks elapse before the next is firmly fixed.[97] He speaks of the rattlesnake chiefly. Fayrer gives the periods in several cobra experiments. In one cobra whose fangs were carefully drawn out on Oct. 7th, new fangs were ‘anchylosed’ to the bone in twenty-four days. In another, thirty-one days elapsed before the new ones were ready for use; and in two others, eighteen days. In all of these cases the new fangs were capable of inflicting deadly injury by the time stated.