504 STUDIES IN GENERAL PHYSIOLOGY 
‘weight of 9 per cent. at this concentration. In this experi- 
ment the solution contained originally 63.3 mg. of HNO,. 
After the muscle was removed, the solution had lost 5.1 mg. 
of the acid. For trichloracetic acid we found a loss of 14 
mg. in two hours. These experiments will be continued. 
Besides the fact that the hydrogen ions enter the muscle, 
these experiments also show that the increase in weight 
which the muscle suffers in the acid solution is much greater 
than the weight of the acid absorbed. There can scarcely 
be any doubt that the increase in the weight of the muscle 
in the acid solution is dependent almost solely, if not entirely, 
upon an absorption of water. But how the hydrogen ions 
can lead to an absorption of water by the muscle can at 
present not be decided definitely. 
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