THE MECHANICS OF HANGING. 507 



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 respir- 

 atory 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 sus- 

 pension, 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 unoxi- 

 dized blood through the lungs ; the left ventricle at first readily pro- 

 pels 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 cessa- 

 tion of the cardiac action is the result. The time during which I have 

 observed the heart's action after dislocation of the cervical vertebras 

 has ranged from two to thirteen minutes. As Professor Haughton 

 has shown, the destructive effect on the neck of the criminal is in pro- 

 portion 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 vertebras 

 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 : 



1 1 W 



-MV 8 = ^26S = WS, 



ii VT til 



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 



