XXIV 
ON THE SIMILARITY BETWEEN THE ABSORPTION OF 
WATER BY MUSCLES AND BY SOAPS? 
I 
Tue difficulty which confronts us in the phenomena of 
the absorption of liquids by tissues consists in this, that we 
have thus far not been able to find any analogies for these 
phenomena in the realm of physics and chemistry. I be- 
lieve to have come upon a series of facts which show that a 
similarity exists between the absorption of water by muscles 
and by soaps. This analogy is, among other things, of im- 
portance because it may help us decide which forces come 
into play in the absorption of liquids. 
Potassium soaps absorb so much water from the air that 
they finally become liquid. The sodium soaps also absorb 
water, but much less than the potassium soaps. The cal- 
cium soaps are useless for washing purposes because of their 
insolubility, or only slight solubility, in water. 
If the sodium of a sodium soap is replaced by calcium, 
water is usually given off; on the other hand, if the sodium 
is replaced by potassium, water is taken up. 
Muscle behaves in exactly the same way. I have shown 
in my earlier publications that a muscle neither takes up nor 
gives off water during the first hour in solutions of neutral 
salts, which are isosmotic with a 0.7 per cent. NaCl solution. 
I found slight variations from this rule in a few salts, espe- 
cially potassium and calcium salts. These variations were, 
though, very slight, and yet too great to attribute them to 
errors in experiment. If, however, the muscles remained 
in the solutions for more than one hour, these differences 
1 Pfliigers Archiv, Vol. LXXV (1899), p. 303. 
510 
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