618 LECTURE XXVI. 



that it results from the coagulation of the protein in muscle, and in fact 

 it is believed to be the protein known as myogen which takes part especially 

 in the process. This is supposed to pass over first into soluble myogen- 

 fibrin, which is subsequently transformed into the coagulated modification. 

 The other protein, myosin, also takes part in the formation of the clot. 1 

 Although the assumption that death-rigor results from a coagulation of 

 the protein has been generally accepted, on the other hand the manner 

 in which the coagulation takes place has been variously explained. Con- 

 siderable attention has always been paid to the fact that an acid reaction 

 appears. This is apparently brought about by the formation of lactic 

 acid, and by the resulting transformation of a part of the diphosphate 

 contained in muscle to monophosphate. Now it has been observed that 

 acid, and especially lactic acid, accelerates the coagulation process. The 

 early appearance of death-rigor after previous active muscular contraction, 

 as, for example, in tetanus, has been attributed to the action of the lactic 

 acid, which is in such cases present in larger amount than usual. Further- 

 more, it has been assumed that a ferment assists in causing the coagulation. 

 The final relaxation, which takes place after an indefinite length of time, 

 is also not perfectly understood. Acids have been supposed to take part 

 in this process also, while, on the other hand, it has also been assumed 

 that autolytic processes come into play. 



In certain directions we are well informed concerning the processes of 

 metabolism which take place in muscles during the exercise of their func- 

 tions. We have already discussed these points. We also know that the 

 liver is apparently in direct relation to the muscles, for, by means of its 

 glycogen store, it satisfies their nutritional requirements. It is not neces- 

 sary that the relation between the liver and muscles should be a direct 

 one. It may be brought about by means of the blood. This has, as we 

 know, a sugar content which is very constant within narrow limits. In 

 case the sugar in the blood is used up by the muscles, it receives a new 

 supply from the liver, the cells of which in such cases at once break down 

 glycogen into sugar. There must also, without doubt, be relations between 

 the general metabolism of the cells and that of the muscles. If, for example, 

 it is desired to fatten with albumin, this can be accomplished well only 

 when there is muscular effort at the time the abundance of albumin is fed. 

 This may be explained on the assumption that under such conditions 

 albumin is assimilated to a greater extent than usual, although it is also 

 possible that the other cells of the body are in some way stimulated to 

 take up more albumin. 



This finishes all that we have to say here with regard to the relations of 

 the individual organs to one another. They are, to be sure, much more 



1 O. von Fiirth: Arch, exper. Path. Phar. 36, 231 (1895). 



