462 GENERATION. 



hausting diseases, this rigidity appears as soon as a quarter of 

 an hour after death. In the case of persons killed suddenly, 

 while in full health, it may not be developed until twenty or 

 thirty hours after death, and continues for six or seven days. 1 

 Its average duration is from twenty-four to thirty-six hours ; 

 and, as a rule, it is more marked and lasts longer, the later 

 it appears. In warm weather, cadaveric rigidity appears 

 early and continues for a short time. When the contraction 

 is overcome by force, after the rigidity has been completely 

 established and has continued for some time, it does not re- 

 appear. The rigidity of the muscular system extends to the 

 muscular coats of the arteries and the lymphatics. 3 It is for 

 this reason that the arterial system is usually found empty 

 after death. 3 The rigidity first appears in the muscles which 

 move the lower jaw ; then, according to the observations of 

 l^ysten, it is noted in the muscles of the trunk and neck, 

 extends to the arms, and finally, to the legs, disappearing in 

 the same order of succession. 4 The stiffening of the muscles 

 is due to a sort of coagulation of their substance, analogous 

 to the coagulation of the blood, and is probably attended with 

 some shortening of the fibres ; at all events, the fingers and 

 thumbs are generally flexed. That the rigidity is not due to 

 coagulation of the blood, is shown by the fact that it occurs 

 in animals killed by haemorrhage. 



According to John Hunter, the blood does not coagulate 

 nor do the muscles become rigid in animals killed by light- 

 ning or hunted to death ; 5 but it is a question, in these in- 



1 Symonds (loc. cit.) observed rigidity in the body of a criminal executed by 

 hanging, eight days after death, but had no opportunity of ascertaining at what 

 time it commenced. 



2 MAGENDIE, Precis elementaire de physiologic, Paris, 1836, tome ii., p. 225. 



3 See vol. i., Phenomena in the Circulatory System after Death, p. 351. 



Parry, in his experiments published in 1816, noted contraction in the arte- 

 ries after death. (PARRY, An Experimental Inquiry into the Nature, Cause, and 

 Varieties of the Arterial Pulse, London, 1816, pp. 16, 46.) 



4 NYSTEN, Recherches de physiologic, Paris, 1811, p. 386. 



6 HUNTER, Lectures on the Principles of Surgery, Philadelphia, 1839, p. 35. 



