METABOLISM. 
are formed. This has, however, been already discussed (p. 750), and 
will be again referred to later on. 
Glycerin has been found to act in some measure as a fat and 
carbohydrate-sparer, but not as a proteid-sparer. 1 Of the total 
amount ingested, from 21 to 37 per cent, is secreted in the urine 
unaltered, when given in large doses. 5 * The sparing effect of glycerin 
on the conversion of liver glycogen into sugar will be subsequently 
referred to. 
Alcohol. — The nutritive value of alcohol has been the subject of 
considerable discussion, and not a few experiments. Some of these 
tend to show that in moderate non-poisonous doses it acts as a non- 
proteid food in diminishing the oxidation of proteid, doubtless by 
becoming itself oxidised. 3 Its action, however, in this respect is 
relatively small, and indeed a certain proportion of alcohol ingested 
is exhaled with the air of respiration. Moreover, in large closes, it 
may act in the contrary manner, increasing the waste of tissue proteid. 4 
It cannot, in fact, be doubted that any small production of energy 
resulting from its oxidation is more than counterbalanced by its 
deleterious influences as a drug upon the tissue elements, and especially 
upon those of the nervous system. 
It is of interest, in connection with this subject, to point out that 
alcohol has been regarded by some physiologists as probably formed 
at a stage in the metabolism of carbohydrates prior to their complete 
oxidation, traces of alcohol having been obtained from fresh tissues by 
distillation with water. 5 
Inorganic substances. — Mineral salts, especially chloride of sodium 
and phosphates of lime and of the alkalies, are essential parts of 
any diet. The following table from Bunge gives the proportions 
K.,0. 
Na 2 0. 
CaO. 
MgO. 
Fe 2 O s . 
P 2 5 . 
CI. 
Beef 
1-66 
0-32 
0-029 
0-15 
0-02 
1-83 
0-28 
Wheat .... 
0-62 
06 
0-065 
0-24 
0-026 
0-94 
? 
Potato .... 
2-28 
0-11 
o-ioo 
0-19 
0-042 
0-64 
0-13 
White of egg 
1-44 
1-45 
0-130 
0-13 
0-026 
0-20 
1 -32 
Peas ..... 
1-13 
03 
0-137 
0-22 
0-024 
0-99 
? 
Human milk 
0-58 
0-17 
0-243 
0-05 
0-003 
0-35 
0-32 
Yolk of egg 
0-27 
0-17 
0-380 
0-06 
0-040 
1-90 
0-35 
Cow's milk 
1-67 
1-05 
1-51 
0-20 
0-003 
1-86 
1-60 
1 
1 I. Munk, Virchow's Archiv, Bd. lxxvi. S. 119 ; Bd. lxxx. S. 39. 
2 Tschinvinsky, Ztschr. f. Biol., Miincheu, 1880, Bd. xv. ; Amschink, ibid., 1888, Bd. 
xxiii. S. 413. 
3 Strassmann, Arch. f. d. ges. Physiol., Bonn, 1891, Bd. xlix. S. 315. Chittenden 
{Journ. Physiol., Cambridge and London, 1892, vol. xii. p. 220), experimenting upon 
dogs, obtained very little influence on proteid metabolism. For the earlier literature 
of this question, cf. C. Voit, op. cit., pp. 169 and 415. 
4 Miura, Ztschr. f. klin. Med., Berlin, 1892, Bd. xx. S. 137. I. Munk obtained similar 
results upon dogs (Vcrhandl. d. Physiol. Gesellsch., 1878-79, No. 6 in Arch. f. Physiol.). 
5 Hoppe-Seyler and Rajewsky, Arch. f. d. ges. Physiol., Bonn, 1875, Bd. xi. S. 
122. 
