544 PHYSIOLOGY. 



a small quantity of magnesium and iron. Phosphoric acid exists in 

 muscle as inorganic phosphates, phosphorus of phosphocarnic acid, 

 and phosphorus of inosinic acid. Carnic acid is identical with anti- 

 peptone. When a muscle works it increases the phosphates in the 

 urine. The gases found in muscle are carbonic-acid gas and oxygen. 



Adipocere is a waxy substance which replaces muscular tissue if 

 bodies be buried in damp soil. It consists principally of a soap made 

 of calcium with palmitic and stearic acids. 



Rigor Mortis. During rigor mortis the muscles become rigid, 

 hard, inextensible, shortened and swollen, as though in a state of 

 contraction. After death, rigor mortis is a constant phenomenon. 

 The muscles to first become rigid are the masseter, temporal, and 

 internal pterygoid. Then it seizes the muscles of the trunk and 

 neck, then the arms and the legs. Tetanus and rigors appear in the 

 same muscles and extend to others in the same way. 



In rigor mortis the thumb is in the palm of the hand and covered 

 with the other fingers, showing that the flexor muscles overcome 

 their antagonistic muscles, the extensors. The jaws are contracted, 

 the eyes are widely open, the head and neck are drawn backward, the 

 abdomen is depressed, the extremities are half flexed, and the feet 

 are extended. 



CAUSE OF RIGER MORTIS. It is due to the myosinogen becom- 

 ing myosin by the action of the myosin ferment with calcium salts. 

 During rigor mortis the muscles become acid, due to sarcolactic acid 

 and acid phosphates, the muscle becomes cloudy, and gives off heat 

 and carbonic acid. After some time rigor mortis passes off and the 

 body becomes relaxed. After fatigue the rigor mortis ensues rapidly 

 after death, lasts but a short time, followed by putrefaction. It is 

 well known that butchers do not kill animals tired by a long walk, 

 but wait for a rest of some days. 



In man it is generally four hours after death that cadaveric 

 rigidity becomes complete. As a rule, it may be said that rigidity 

 begins two hours after death, reaching its maximum two hours later. 



A particular kind of rigor mortis has been observed by military 

 surgeons. Soldiers while in full activity have been struck by pro- 

 jectiles and have been seen to become stiff instantaneously. It is a 

 sort of rigor mortis which seizes all of the muscles of the body imme- 

 diately after death. 



Influence of Temperature. Animals which have died in heated 

 chambers become rigid very quickly and the rigidity disappears as 

 quickly. 



