RIGOR MORTIS 393 



may not become rigid before tlie lower. Tlie time of onset is ex- 

 tremely variable, but the following general rules may be stated: All 

 conditions that lead to excc^ssive muscular metabolism, with its re- 

 sulting increase in the acidity of the muscle fluids, will hasten the 

 onset of rigor mortis; thus, people killed suddenly during violent 

 activitj'' may remain almost in the position in which they met death. 

 Acute fevers, strychnine poisoning, tetanus, etc., cause likewise a 

 rapid onset of rigor, which may, indeed, appear almost simultane- 

 ously with death or even before the heart has stopped beating. 

 When a healthy individual meets death without 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 development 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. ''^ 



The duration of rigor mortis also is influenced by many factors. 

 In general, it may be said that the duration is in inverse relation 

 to the rapidity of onset, and directly to the musculature of the in- 

 dividual. 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 postmor- 

 tem, 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. ^^ 



The chemistry of the changes involved in rigor mortis has been 

 a much-contested problem. Two chief doctrines have been sup- 

 ported: one that rigor was not essentially different from ordinary 

 muscular contraction except in degree, and perhaps 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 protein w'hich formed 

 the clot is called myosin, and its coagulable antecedent, myosinogen. 



This experiment has been since repeatedly verified and amplified, 

 especially by v. Fiirth and by Halliburton,^'^ who have separated more 



** Rigor mortis may develop in the dead fetus while in the womb, but it gen- 

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

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



" See Mangold, Pfltiger's Arch., 1903 (96), 498. 



" "Chemistry of Muscle and Nerve," 1904. 



