some cases that the cardio-inhibitory center may be stimulated, or the vagi compressed, so as to immediately arrest the beat of the heart, yet I am convinced that this is the exception, and not the rule. The respiratory and vaso-motor centers are at once paralyzed. I have never seen even the faintest involuntary gasp, and the arteries feel at once to have lost tone. The excito-motor ganglia of the heart keep up its action, in the majority of cases, for some minutes independently of the central nervous system, and its arrest is probably brought about by a process of asphyxia. The immediate cessation of all respiratory movements deprives the heart of all assistance in carrying on the circulation, and prevents the lungs from becoming surcharged with blood, as in ordinary cases of asphyxia, but the other signs of death from that cause are usually present, such as turgescence of the right side of the heart and general venous system; great lividity of the face; swelling, and perhaps protrusion, of the tongue. It should be remembered that these latter signs are best observed during suspension, because when the body is taken down hypostasis occurs quickly owing to the great fluidity of the blood, the tongue recedes within the mouth, and the general lividity on the upper surface of the body disappears, to reappear in the most dependent parts. The right side of the heart soon becomes incapable of driving the unoxidized blood through the lungs; the left ventricle at first readily propels the blood into the lax arteries, but soon the supply is diminished and the contraction becomes feeble, and at the same time the blood is accumulating in the venous system, and thus tending to equalize the pressure, and so at last the left ventricle is unable to drive its modicum of blood through the systemic capillaries. We have thus at the same time both sides of the heart unable to perform their work, and cessation of the cardiac action is the result. The time during which I have observed the heart's action after dislocation of the cervical vertebræ has ranged from two to thirteen minutes. As Professor Haughton has shown, the destructive effect on the neck of the criminal is in proportion to the vis viva which is acquired by the weight of the culprit and length of the drop; and, if the drop be long enough, the vertebræ are certain to be dislocated, no matter what be the position of the ring or thickness of the rope. The vis viva in any case is equivalent to half the mass multiplied by the square of the terminal velocity. Let W represent the weight of the criminal, and S the length of the drop, then the formula will be:
or the weight of the criminal multiplied by the length of the drop expresses in foot-pounds the amount of work expended on the neck of the criminal. I have not complicated the formula with the co-efficient of the elasticity of the rope—which is very slight—as we will devote some attention to the character of the rope further on. I would now
