THE RELATION OF DIET TO DISEASE 427 
last being the factor most at fault. The calcium and 
phosphorus are both so low that at the best the animal 
could only be in equilibrium, while any drain of the fixed 
bases would sooner or later have to be replenished from 
the calcium and phosphorus storage depots, the bones. 
Osteomalacia is most marked in the Cebidae, monkeys 
whose diet is even lower in these same elements : calcium 
.025, phosphorus .116, and iron .0008 per 100 grams of 
food. The inorangic composition of all animals is grossly 
similar ; the typical digestion developed from the habitual 
diet of the animal explains the more apparent changes 
and variations in their reactions to certain deprivations. 
Ikregularities of Inoeganic Metabolism. 
Twelve essential elements are present in the body, 
namely: carbon, nitrogen, hydrogen, oxygen, phos- 
phorus, calcium, sulphur, sodium, chlorine, potas- 
sium, iron, magnesium. Of these, five are furnished 
by the protein molecule and three of the five are 
duplicated in the fats and carbohydrates; the remain- 
ing seven must be present in the mineral ash. These 
elements functionate in three ways, (1) as constituents 
of bone, (2) as essential elements of organic com- 
pounds, (3) as soluble salts in body fluids. Chlorine, 
sodium, sulphur are supplied in sufficient quantity with 
most diets. In the case of chlorine, marked differences 
exist between the herbivores and carnivores. The meat- 
eating mammals easily acquire sufficient sodium chloride 
from the flesh and blood of their victims, while the 
herbivores on the other hand, find in their vegetable food 
large amounts of potassium and very little sodium or 
chlorine which must therefore be acquired separately. 
Both omnivores and herbivores crave salt, probably 
because this large potassium content of vegetable food 
tends to increase the sodium elimination. A deprivation 
of salt always leads to a distaste for foods rich in po- 
tassium. So far as is known excessive sodium stimulates 
