24 PHYSIOLOGY AND TOXICOLOGY 



close the jaws, under circumstances Avliich do not demand the ejection of venom, 

 we must suppose, either that the anterior temporal is, at times, functionally inactive, 

 or else that some provision exists for restraining the flow of poison, when the gland 

 is incidentally comj^ressed during the ordinary movements of the lower jaw, as in 

 gaping (a common action with snakes), deglutition, etc. 



The closure of the duct is provided for in two ways, one of which is peculiarly 

 ingenious. The first and most effective of these is the sphincter, which I have 

 already described. The second consists in a peculiar relation between the maxillary 

 bone and the duct. The antero-lateral surface of the bone is somewhat rounded, 

 and the duct being confined at the base of the bone, and also perfectly fixed at its 

 junction with the fimg, it happens that when the fang tooth lies flexed in the 

 mouth, the maxillary portion of the duct is stretched over the rounded shoulder 

 of bone upon which it rests, thus flattening, and closing its canal more or less 

 completely. 



It is worthy of remark, that the abrupt curve of the duct under the eye, has, 

 also, a mechanical value. First, as an additional means of interrupting the flow of 

 venom, when the fang is not in use, and, second, as a provision for preventing 

 injury to the duct, when, during the action of fixing tlie fang, the duct is drawn 

 backward by the muscles, and forward by the sudden and momentary flexion of 

 the fang, which occurs at this time. Under these two forces, the bend in the duct 

 is temporarily obliterated. 



The power with which the venom is ejected from the tooth, depends somewhat 

 upon the amount contained in the gland and its ducts. When the snake fails to 

 strike the object aimed at, the poison is sometimes projected several feet. In one 

 case which is known to me, it was thrown into the eye of a man standing five or 

 six feet from the snake, when it struck upwards at a stick held above its coil.^ 



■* For an account of many facts in connection with snakes, wliieli are of popular scientific interest, but 

 remote from my present subject, tlie reader will do well to consult Professor Leconte's paper, Shaw's 

 Zoology, the various Encyclopedia articles, and the memoir of Prof. Dumeril, to which I have already 

 referred. 



The great tenacity of life on the part of snakes, is alluded to by several of these authors, and is 

 well known in the form of a very singular popular belief. It is certainly very remarkable in the Rattle- 

 snake, whose reflex motions are admirably retained for some hours after decapitation, and occasionally 

 are seen as late as the 36th hour. At this late period, they consist in wave-like movements, which run 

 from the tail upwards, and are most readily exeited by pinching the parts about the cloaca. Immediately 

 after the head has been cut off, the body writhes slowly along the floor, or, if hung up, returns on itself, 

 twining the pendant trunk around the tail. If, when the body is entirely fresh, we seize the tail, the 

 headless trunk frequently returns on itself, in the effort to strike the offending hand. Occasionally, this 

 movement is so perfectly executed, that the bleeding and headless trunk smites the operator's hand before 

 it can be withdrawn. In one or two instances, persons who were ignorant of the possibility of this 

 movement, have been so terrified at the blow which has greeted them, as to faint on the spot. To hold 

 thus the headless snake, has been made a test of firmness in some parts of the West ; and few have been 

 found composed enough to retain the tail until the innocent, but ghastly stump, struck the hand. Indeed, 

 any one who may try this little experiment, will discover that it is no easy task to keep* steady grasp upon 

 the tail, even when, in ineffectual efforts, the bleeding neck is thrown towards the irritated parts, but does 

 not fully succeed in reaching it. It is interesting to observe that, while the person whose nerves are thus 

 tried, looks at the snake, he can scarcely ever so control liimself as to be unmoved ; but, if he close his 



