DEATH-STIFFENING. 89 



during death-stiffness it was formerly believed that the 

 latter was to be regarded as a true contraction, as a last 

 exertion of muscular force in which the muscle took 

 leave of its peculiar capacity. There is, however, nothing 

 to show that this shortening which takes place at death, 

 and which may moreover be hindered by the application 

 of even a slight weight, corresponds in any way with 

 the real state of activity. All the phenomena of mus- 

 cular rigidity are, indeed, more fully explained by the 

 assumption that some constituent part of the muscle 

 which is liquid in the living muscle becomes fixed or 

 coagulates. Death-stiffening would accordingly be a 

 process analogous to the coagulation of the blood, which 

 after death or after it has been allowed to escape from 

 the blood-vessels becomes firm, in consequence of the 

 fact that one of its constituents, the blood fibrous matter, 

 or fibrine, secretes itself as a solid. This view of death- 

 stiffness was first expressed by E. Briicke and was after- 

 ward confirmed by Kiihne. If the muscles of a frog are 

 freed from all blood by injection with an innocuous 

 fluid, such as a weak solution of common salt, and are 

 then pressed, a fluid is obtained which represents part 

 of the liquid contents of the muscle-fibres. If this fluid 

 is allowed to stand for some hours in the ordinary tem- 

 perature of a room, a flaky clot forms in it at the same 

 period at which other muscles of the same animal 

 undergo death-stiffening. The expressed muscle-fluid 

 is originally quite neutral ; but while the clot is forming 

 it becomes continually more acid. The resemblance of 

 the process in this muscle-fluid to that in the muscle 

 itself is, therefore, such as to justify the assumption 

 that at the same time a coagulation, simultaneously 

 with an acid-formation, takes place within the muscle 



