Tue PHYSIOLOGICAL ErFrects oF Ions 473 
the protoplasm, and consequently its osmotic pressure, is 
affected differently by the different ions—of which we will 
say more immediately —the agreement between the values is 
satisfactory enough for proving the validity of Van ’t Hoft’s 
theory of osmotic pressure for the life phenomena of cells. 
Barium chloride, however, seems to be an exception. 
VII. ON THE EFFECT OF POTASSIUM CARBONATE AND SODIUM 
CARBONATE SOLUTIONS UPON THE MUSCLE 
If solutions of Na,CO, and K,CO, of the same concen- 
tration as a 0.7 per cent. NaCl solution are prepared, muscles 
immersed in them increase markedly in weight. Table XV 
gives the increase in weight of the muscles in these solutions 
after one hour. 
TABLE XV 
I II 
Wa Oc seavewnsaut T.1¢ 7T.1¢ 
Oa anette 5.1 6.8 
The muscles showed the glassy appearance of a muscle 
which has been in a weak solution of an alkali. The order of 
magnitude of the absorption of water also corresponds with 
the effects of an alkali. According to the theory of dissocia- 
tion, this effect is brought about in the following way: The 
potassium carbonate is dissociated in part into potassium and 
CO, ions; as carbonic acid is a very weak acid—that is to 
say is only slightly dissociated—each CO, ion combines 
with two H ions to form carbonic acid. Two negatively 
charged OH ions must, in consequence, go into solution,’ and 
these bring about both the alkaline reaction of the solution 
and the absorption of water by the muscle. We are dealing 
in this case, therefore, not with potassium or carbonate 
effects, but with the effects of hydroxyl ions. 
1More correctly form 2KOH, which, however, at this degree of dilution is dis- 
sociated to a high degree. [1903] 
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