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LACK OF MINERAL SUBSTANCES. 899
If water is withdrawn for a certain time, as Landauer and espe-
cially Straub have shown, it has an accelerating influence upon the
decomposition of protein. This increased destruction has, according to
Landauer, the purpose of replacing a part of the water removed, by the
production of water by means of the increased metabolism. The depriva-
tion of water for a short time may, according to Spiegler, 1
especially in
man, cause a diminution in the protein metabolism by means of a reduced
protein absorption.
Lack of Mineral Substances in the Food. In the previous chapters
attention has repeatedly been called to the importance of the mineral
bodies and also to the occurrence of certain mineral substances in certain
amounts in the various organs. The mineral content of the tissues and
fluids is not very great as a rule. With the exception of the skeleton,
which contains as average about 220 p. m. mineral bodies (Volkmann 2
),
the animal fluids or tissues are poor in inorganic constituents, and the
quantity of these amounts as a rule, only to about 10 p. m. Of the
total quantity of mineral substances in the organism, the greatest part
occurs in the skeleton, 830 p. m., and the next greatest in the muscles,
about 100 p. m. (Volkmann).
The mineral bodies seem to be partly dissolved in the fluids and partly
combined with organic substances, but nothing definite can be given as
to the kind of combination, or whether they occur in stoichiometric
proportions, or whether they are simply adsorption combinations. In
accordance with this the organism persistently retains, with food poor
in salts, a part of the mineral substances, also such as are soluble, as the
chlorides. On the burning of the organic substances the mineral bodies
combined therewith are set free and may be eliminated. It is also
admitted that they in part combine with the new products of the com-
bustion, and in part with organic nutritive bodies poor in salts or nearly
salt-free, which are absorbed from the intestinal canal and are thus retained
(Voit, Forster 3
).
If this statement is correct, it is possible that a constant supply of
mineral substances with the food is not absolutely necessary, and that the
amount of inorganic bodies which must be administered is insignificant.
The question whether this is so or not has not, especially in man, been
sufficiently investigated; but generally we consider the need of mineral
1
Landauer, Maly’s Jahresber., 24; Nothwang, Arch. f. Hyg., 1892; Straub, Zeitschr.
f. Biol., 37 and 38; Spiegler, ibid., 41.
2
See Hermann’s Handbuch., 6, pt. 1, 353.
3
Forster, Zeitschr. f. Biologie, 9. See also Voit, in Hermann’s Handbuch, 6,
Part 1, 354. In regard to the occurrence and the behavior of the various mineral
constituents of the animal body see the work of Albu and Neuberg, Physiologie und
Pathologie des Mineralstoffwechsel, Berlin, 1906.
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