WATER ABSORPTION BY MUSCLES AND SOAPS 511 



became very marked; after eighteen hours, for example, it 

 was found that the muscle kept in an isotonic KC1 solution 

 had gained from 40 to 50 per cent, in weight; that a 

 muscle in a CaCl 2 solution lost about 20 per cent, in weight; 

 that the weight of a muscle in LiCl remained practically 

 unchanged ; while that in NaCl solution had increased a few 

 per cent, in weight. The following gives a summary of 

 these results: 



TABLE I 



Changes in weight in the gastrocnemii of frogs kept in solutions equimolecular 

 with a 0.7 per cent. NaCl solution. Length of the experiment, 18 hours. An 

 increase in weight (expressed in per cent, of the original weight of the muscle) 

 is designated by a + ; a loss in weight by a . 



LiCl ..... -\% NaCl . . ..+ 6# KC1 . . . .+45 CaCl 2 . . -20 

 LiBr ..... -1 NaBr....+ 7 KBr....+41 

 Lil ...... +3 Nal ..... +10 KI ...... +45 



The figures given in this table were corroborated by a 

 large number of experiments. Variations due to individual 

 differences in the muscles and variations in the temperature 

 are unavoidable, but the order of magnitude of the results 

 obtained was always about the same as those given above. 



Since the difference in the degree of dissociation of the 

 potassium and sodium salts is very slight, it is of course ex- 

 cluded that differences in osmotic pressure, due to differ- 

 ences in the degree of dissociation, should be responsible 

 for the results obtained. 



The potassium and sodium salts of other acids, such as 

 the sulphates and oxalates, also show these differences, 

 though not so markedly. 



Wallace and Cushny believe that only the anions and 

 not the cations of salts play a role in the absorption of 

 water from the intestines. 1 If this is true, the absorption 

 of liquids by the intestine must be governed by entirely 

 different laws from those which govern the absorption of 



1 WALLACE AND CUSHNY, American Journal of Physiology, Vol. I, p. 411. 



