An introduction to pathology and morbid anatomy / by T. Henry Green.

  • Green, T. Henry (Thomas Henry), 1841-1923
Date:
1900
Catalogue details

Licence: In copyright

Credit: An introduction to pathology and morbid anatomy / by T. Henry Green. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    37/618 (page 21)
    POST-MORTEM CHANGES 2] ■contraction. It comes on as soon as the muscles have lost theif iiTitability—i.e., their cajiability of responding to artificial stimulation ; in other words, as soon as the nutritive processes have comjoletely ■ceased. The time of its appearance will therefore dejiend upon the state of nutrition of the muscles at the time' of death ; the more healthy and vigorous this is, the longer will be the intei-val before nutritive jjrocesses completely cease, and consequently the longer before rigor mortis supervenes. Its duration and its intensity are in direct proportion to the lateness of its appearance. In people, for example, who are in perfect health and die suddenly, as from accident, the rigor mortis does not usually come on until from ten to twenty- four hours after'death : it is very marked, and often lasts two or three days. In those, on the other hand, who die from some exhausting- disease, as from chronic phthisis, in which the nutrition of the muscles has become much im])aired, the rigor mortis appears very soon, some- times as early as ten minutes after death ; it is very slight, and may pass off in less than an hour. It has been said that in cases of death Irom lightning, and from some of the severer forms of the adynamic levers the rigor mortis is entirely absent. It is doubtful, however, if this is the case : the rigor moi-tis has jirobably escajjed observation, •owing to its early supervention and rapid disappearance. With regard to the nature of the change, Kiihne and others have shown that it is reall}^ owing to the coagulation of the muscle-plasma and the formation of a proteid clot—myosin. Ihe coagulation is attended by the liberation of a free acid (sarcolactic). Thus are/ j)roduced the firmness, hardness, and opacity of the muscle which are together characteristic of rigor mortis. This change is not confined to voluntary muscle; a similar coagulation of the ]n-otoplasm takes place -after death in all involuntary muscle-fibres. As soon as decomposition commences, rigor mortis disappears. Ihe transverse striation of the fibres then becomes indistinct, and ^ives j)lace to irregular rows of granules and fat-molecules. In the meantime the muscle softens, its sarcolemma disa))pears, and ultimately nothing remains but a soft structureless debris. In adipose tissue, the cells diminish in size, owing to the escape of the fluid fat, which diffuses itself throughout the surrounding structures. The fibres of the connective-tissue swell, become opaque, and ultimately liquefy. In nerve-fibre.s, the white substance of Schwann coagulates and collects into small drops within the neurilemma. Cartilage, bone and hair resist tlie ))utrefactive ]irocess longer than any of the other tissues, and are the least altered bv it.