RIGOR MORTIS 327 



out previous exertion, rigor does not usually appear for four or 

 six hours, but will be hastened by heat and retarded by cold. 

 Death from hemorrhage or asphyxia is followed by a slow de- 

 velopment of the rigor. Under ordinary conditions rigor 

 usually begins between the first and second hour after death 

 and is complete in one or two more hours. 1 



The duration of rigor mortis also is influenced by many fac- 

 tors. In general, it may be said that the duration is in direct 

 relation to the rapidity of onset, and also to the musculature of 

 the individual. Therefore, in an emaciated individual dying 

 with fever, rigor may appear and disappear again within two or 

 three hours, or, indeed, escape observation altogether. The 

 body of a muscular man dying from accident or hemorrhage 

 may, on the other hand, show rigor for two or three weeks if 

 kept in a cold place. Once the rigor has been broken by force, 

 it does not again return. 



Rigor mortis may be produced even before death, through 

 poisons (monobromacetic acid, quinine), and its occurrence, 

 even postmortem, does not necessarily mean that the muscle is 

 dead, for if the part is transfused with a salt solution the 

 rigor may be removed, and the muscle will then be found to 

 react to stimuli. This indicates that the chemical changes of 

 rigor mortis are not very profound. 2 



The chemistry of the changes involved in rigor mortis has 

 been a much-contested problem. Two chief doctrines have 

 been supported : one that rigor was not essentially different 

 from ordinary muscular contraction except in degree, and per- 

 haps due to a loss of inhibition to contraction. The other 

 looks upon it as a coagulation similar to the coagulation of the 

 blood ; and this idea, it may be said, has had the most general 

 acceptance. Briicke in 1842 supported this view, and in 1859 

 Kiihne extracted from muscle a plasma which coagulated like 

 ordinary blood plasma. The proteid which formed the clot is 

 called myosin, and its coagulated antecedent, myosinogen. 



This experiment has been since repeatedly verified and am- 

 plified, especially by v. Fiirth and by Halliburton, 3 who have 

 separated more definitely the proteids concerned in coagulation, 

 and found them to be globulins. There seem to be two : one, 

 coagulating at 47, called paramyosinogen (Halliburton), con- 

 stitutes but about one-fifth of the total clotting globulin, and 



1 Rigor mortis may develop in the dead fetus while in the womb, but it 

 generally disappears within five or six hours. Literature by Wolff, Arch. f. 

 Gyn., 1903 (68), 549 ; Das, Brit. Jour, of Obstet., 1903 (4), 545. 



2 See Mangold, Pfliiger's Arch., 1903 (96), 498. 



3 " Chemistry of Muscle and Nerve, " 1904. 



