A text-book of physiology : for medical students and physicians / by William H. Howell.
- William Henry Howell
- Date:
- 1907
Licence: Public Domain Mark
Credit: A text-book of physiology : for medical students and physicians / by William H. Howell. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![Usually there is a certain sequence, the order given being the jaws neck, trunk, upper limbs, lower limbs, the rigor taking, therefore, a descending course. The actual time of the appearance of the rigidity varies greatly, however; it may come on within a few minutes or a number of hours may elapse before it can be detected, the chief de- termining factor in this respect being the condition of the muscle itself. Death after great muscular exertion, as in the case of hunted animals or soldiers killed in battle, is usually followed quickly by muscle rigor; indeed, in extreme cases it may develop almost imme- diately. Death after wasting diseases is also followed by an early Pig. 25.—Curve of normal rigor mortis, gastrocnemius muscle of frog. The curve was obtained upon a kymographion making one revolution in eight days. The murks on the line below the curve indicate interval, of six hours. It will be seen that the shortening required eighteen hours, the relaxation about seventy-two hours. rigor, which in this case is of a more feeble character and shorter duration. The development of rigor is very much hastened by many drugs that bring about the rapid death of the muscle substance, such as veratrin, hydrocyanic acid, caffein, and chloroform. A frog's mus- cle exposed to chloroform vapor goes into rigor at once and shortens to a remarkable extent. Rigor is said also to occur more rapidly in a muscle si ill connected with the central nervous system than in one whose molor nerve has been severed. After a certain interval, which also varies greatly,— Iron i one to six days in human beings,—the rigidity passes off, the muscles again become soft ;nid flexible; this phenomenon is known as the release from rigor. In the cold-blooded animals the development of rigor is very much slower than in warm-blooded animals, Upon an isolated frog's muscle the most striking fact regarding rigor mortis is the shortening that the muscle undergoes. This shortening or contraction comes on lowly, as is shown in the accompanying figure, bul in extent ii exceed the simple contraction obtainable from the living muscle by mean- of a maxima] stimulus. This pari of the phenomenon i . however, much less marked apparently in mammalian muscle,](https://iiif.wellcomecollection.org/image/b21218183_0060.jp2/full/800%2C/0/default.jpg)
