On the coagulation of muscle plasma

The conception of rigor mortis as a process of solidification of the liquid contents of the muscle cell relies, for its experimental foundation, on the work of Kühne (1, 2). In his 'Unterschungen über das Protoplasma,' published in 1864, this author describes attempts made to prepare a sample of muscle plasma in a state approximation as nearly as possible to the condition in vivo. By a variety of methods he obtained a clear viscous liquid from amphibian muscle, which, on warming to room temperature, rapidly set to a firm gel, at the same time changing from a slightly alkaline to a slightly acid reaction. The analogy between this process and the processes occurring during the death change in muscle was so striking, that a theory of the causation of rigor mortis, which attributed the whole phenomenon to the spontaneous coagulation of the muscle plasma, was constructed on this evidence alone (Kühne (1), Hermann (3)). So far as a careful scrutiny of the literature can elicit, the work has not been repeated or confirmed, but Halliburton (4), by a modification of Kühne's technique, extended the latter's observations to mammalian muscle, and succeeded in obtaining a sample of plasma which set to a gel at ordinary temperatures. Not only do these observations throw light on rigor mortis, but their implication with regard to the existence of a liquid plasma in muscle, capable of easy expression, is of the first importance from the point of view of the constitution of muscle. This work of Kühne and Halliburton forms, therefore, an obvious starting point for an investigation, of which the present account covers the preliminary stages, into the physical state of the muscle fibre, and the changes involved in rigor mortis.