SCIENCE LETTER FROM PARIS. 49 



the case of soft soap, is potash; and for hard, soda; soap should be exempt from 

 too much unsaponified fat, in order not to leave the hands pitchy ; the water, if 

 calcareous, will cause the soap to curdle or waste, and such will continue till 

 the soap has saturated all the lime in the water. 



The discussion is still continued in scientific circles as to what constitutes the 

 surest indications of death. The rigidity of the remains, say Jhe majority, al- 

 though that has set in before the extinction of life. The flexibility of the 

 members is a proof of the absence of death; but such can exist along with death. 

 Bichat maintained, that in the case of the asphyxiated, no stiffness of the body is 

 found, and Hunter asserted that such was absent in the case of death from light- 

 ning ; a fcetus does not become rigid after death, according to many. However, 

 rigidity is a phenomenon very constant after every form of death, and observed 

 ahke with verterbrate and invertebrate animals. Though this stiffness be peculiar 

 to the muscles, other tissues, as the brain, the liver, the kidneys, present a rigidity 

 analogous, while less marked. The rigidity is presumed to be due to the coagu- 

 lation of the albuminoid matters which enter into their constitution. What is the 

 difference between congelation and rigidity ? A muscle in the latter condition 

 has still a certain degree of elasticity, but a frozen muscle is hard as metal, and, 

 when struck, sounds ; when pressed, emits the cracking noise peculiar to tin. 

 When does rigidity set in? The moment is very variable; immediately after 

 death in some cases, and later in others. Sardines and whitebait become rigid 

 immediately after asphyxiation. There is a close connection between this stiff- 

 ness and muscular irritability. All muscle separated from the nutritive action of 

 liquid blood passes through three stages; increase of excitability, decrease of 

 same, rigidity and putrefaction. The stiffness is presumed to commence by the 

 trunk and neck, next the thoracic membranes, and afterward the abdomen. 

 The muscles of the jaw, according to some authorities, are the first affected. Up- 

 ward of twenty-seven per cent of corpses become rigid within four hours, and 

 twenty per cent within six hours. The turning in of the thumb against the palm, 

 of the hand, to be covered by the fingers, is not always a sign of death. There is a 

 rigidity, a kind of catalepsy, peculiar to battlefields ; thus a soldier has been found 

 dead and stiff, one hand holding the bridle of his horse, the other his carabine, 

 one foot in the stirrup and the other on the ground ; another soldier, whose head 

 had been carried off by a shell, held firmly in his hand a goblet full of water that 

 he was in the act of drinking. These phenomena can be reproduced by killing 

 rabbits. A sardine expires instantaneously when removed from the water, but a 

 conger will live for a long time ; birds become stiff sooner than rabbits, and the 

 latter more rapidly than dogs. The influence of heat is an important point. 

 Cold is declared to hasten rigidity; but an animal may be rigid and yet warm, as 

 is illustrated in shooting game. Further, the cooling of a dead body proceeds 

 slowly, often taking twenty-four hours to equal that of the . surrounding air, be- 

 cause chemical changes take place a long time after life. In the case of deceases 

 from cholera, madness and lockjaw, the body actually becomes warmer by two 



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