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at by many, has its dangerous side. Mechanical labour the muscles 
can perform at the cost of food free from nitrogen; however to be 
of service to the organism, also in other respects, by means of the 
tonus, they want protein. 
The opinion has often been pronounced that the stiffening of the 
muscles after death should be considered as a last contraction of the 
muscles. Especially Hermann has indicated the agreement between 
the changes the muscle undergoes at coagulation and those which 
are observed in the contraction. In the above mentioned paper of 
Yon Furth and Schwarz it is proved that it is such substances espe¬ 
cially, which are capable of promoting the coagulation of the muscle- 
plasma, that raise the labouring-faculty of the muscles. 
It seems that the agreement does not refer to the rapid contraction 
but to the tonus. We have found an increase of the quantity of 
creatine in frog-muscles which were stiffened by immersion in water 
of 42° or 45° C. In four experiments the increase amounted on an 
average to 0.305 mgr. creatinine on 1 grm. of the muscle (min. 
0.204, max. 0.460 mgr.). 
For the rabbit the investigation offered some difficulties, because 
here the decomposition of* creatine, proved by Gottlieb and Stangassinger 
plays an important part and the so much thicker rabbit-muscle is 
not so rapidly coagulated as the thin muscles of the frog. When, 
however, the errors arising from this are avoided as much as possible, 
also in the majority of cases, both with the red and the white 
muscles of the rabbit, a distinct increase of the quantity of creatine 
was observed in the stiffened muscles. 
Also in the investigation into the spontaneous stiffening of muscles 
after death, the postmortem disappearance of creatine has to be taken 
into consideration. When, however, the muscles of one side of the 
body were, directly after death, put in hydrochloric acid and the 
corresponding muscles of the other side after three or four hours 
when the stiffening had been well developed, each time there was 
found more creatine in the coagulated muscles than in those examined 
in a fresh condition. In the four cases dealt with in this way, we 
found an uncommonly great difference in one, and in the three others 
on an average 0.260 mgr. of creatinine more (min. 0.124, max. 0.336 
mgr.). The description in details of these and the other observations 
mentioned we intend to give somewhere else. 
From our investigation we think we are entitled to derive that in 
the muscles of vertebrate animals, at the heat-coagulation and the 
postmortem rigour as well as the tonus, a chemical process takes place 
which causes the origination of creatine. 
