390 RETROGRESSIVE CHANGES 



carbon dioxide, 27.6 per cent. ; other gases, probably chiefly nitrogen, 

 8.1 per cent. 



RIGOR MORTIS 15 



This topic may be appropriately considered in connection with cell 

 death, since it is a characteristic change occurring after general 

 death. All forms of muscle, striped, smooth, and cardiac, undergo 

 this change, which is shown by a shortening and thickening of the 

 muscle, which also becomes opaque and hard. Rigor mortis begins 

 first in the heart muscle, according to Fuchs,^'' but it is generally 

 observed first in the eyelids, then in the muscles of the jaw, from 

 which point it proceeds downward, although the ujjper extremities 

 may not become rigid before the lower. The time of onset is ex- 

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

 conditions that lead to excessive 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 

 activity 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 liealthy 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 nniscle is dead, for if the part 

 is transfused with a salt solution the rigor may be removed, and the 



15 Literature, see v. Fiirlli, TTini(ll)ucli d. Tlioclipm., 100!) (II (2), 252; also 

 Molt/cr and Aiicr, Jour. Kxp. Med., IltOS (10), 45). 



inZeit. f. Ileilk., IHOO (21, Patli. Abt.), 1. 



17 Kifror mortis may develop in tlie dead fetus wliile in the womb, but it cen- 

 erallv disajipears witliin live or six lioiirs. Literature hv WolfT, Areli. f. Gvn., 

 ]!)0:}' (G8), 549; Das, Brit. Jour, of Obstet., 1903 (4), 545. 



