The proteids of muscle / by G.N. Stewart and Torald Sollmann.

  • George Neil Stewart
Date:
[1899?]
Catalogue details

Licence: Public Domain Mark

Credit: The proteids of muscle / by G.N. Stewart and Torald Sollmann. Source: Wellcome Collection.

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    slices, expressing it, and filtering tlie expressed liquid in the cold. This is the case even when saline extracts of the same heart or of the spontaneously formed clot contain no myosinogen. 5. It is not possible to obtain pure paramyosinogen by adding 50 grm. of magnesium sulphate to 100 c.c. of a 5 p.c. magnesium sulphate extract of skeletal muscle and dissolving the precipitate in water. Only a small amount of proteid goes into solution in the water, and this consists of a mixture of paramyosinogen and myosinogen. 6. It is not possible by saturating with magnesium sulphate crystals a 5 p.c. magnesium sulphate extract of muscle, to completely free it from proteids coagulating below 60°. 7. By long-continued heating at 40° or even at lower temperatures it is possible to precipitate the whole of the paramyosinogen in an insoluble form either from its solutions or in situ in the muscle fibres. A distinct jelly-like coagulum is often produced without dilution in a 5 p.c. magnesium sulphate extract of muscle placed in a water-bath at 35°—40°. 8. The relative amount of paramyosinogen and myosinogen in extracts of one and the same skeletal muscle was found, within the limits of error of the quantitative methods used, the same in early rigor (a few hours after death), in well-established rigor (48 hours after death), and after rigor has passed off without putrefaction (7 days after death, in a room at a temperature a few degrees above freezing point). The resolution of rigor cannot, therefore, be due to the conversion of spontaneously coagulable myosinogen into non-coagulable paramyosinogen, an explanation which suggested itself not unnaturally at a time when solutions of pure paramyosinogen were supposed to be incapable of clotting at a temperature below that of ordinary heat-coagulation. 9. It seems, nevertheless, probable that paramyosinogen and myosinogen are not absolutely independent of each other; and it is possible that under certain conditions the one may be converted into the other. 10. By mechanical means (pressure with the fingers) such changes may be produced in fresh muscles that ordinary heat rigor (i.e. the rigor which takes place when a muscle is heated for a very short time to a temperature below the ordinary heat-coagulation temperature of paramyosi¬ nogen) can no longer be brought about, and this when the escape of liquid from the muscle has been entirely prevented. Here, although all the spontaneously coagulable constituents of the muscle are still within the anatomical muscle, the alteration of their normal position in the muscle fibres seems to hinder the development of the rigidity which, had they clotted in their normal situation, would have been produced. This experiment evidently has a bearing on the well-known fact that ordinary rigor, once established, can be broken down by mechanical means, and does not then recur.
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