76 USES 
these are starch granules. Outside the mass of large cells is a single 
layer of squarish cells, containing minute granules of uniform size, 
known as aleurone grains. Isolated cells of aleurone grains some- 
times occur in the central mass of the grain. Investing the row of 
squarish cells are several very thin fibrous layers which constitute 
the testa and pericarp, or, in popular language, the skin of the grain. 
The starch granules, it is hardly necessary to remark, belong to 
the group of carbohydrate nutrients (heat and force producers) ; 
the aleurone grains are highly complex bodies belonging to the 
group known as proteids or albuminoids (flesh formers), the essen- 
tial characteristic of which is, that nitrogen enters into their com- 
position. The fibrous layers consist largely of cellulose, indigestible 
by man, but contain a considerable quantity of oil and mineral 
matter, the latter chiefly potash and phosphoric acid. The embryo 
(fig. 1) is rich in all the nutrients. The composition of an average 
sample of wheat grains is, in 100 parts : water, 14 ; albuminoids, 12 ; 
starch (including about 4 per cent. of dextrine and sugar), 68 ; fat or 
oil, 1°7 ; salts, 1°6; cellulose, 2°7. The sum-total of the nutrients, or 
nutrient value, is 84 (the oil being expressed in its starch equivalent, 
I part oil=2} parts starch). The most important consideration in 
these percentages is the proportion of albuminoids to carbohy- 
drates and fat ; in the above analysis this proportion, or nutrient 
ratio as it is often termed, is 1:63; in other words, to one part of 
flesh formers, there are six parts, by weight, of heat or force pro- 
ducers ; the nutrient ratio of a standard dietary is 1:44. The 
principal variation in the composition of different kinds of wheat 
is in the proportion of albuminoids to starch, the former oscillating 
between Io and 16 per cent., or even higher in the horny translucent 
wheats of warm dry climates. 
The large amount of starch in the cereal grains gives them a 
high dynamic value as a food substance. 1 Ib. of the crumb of 
bread, if digested and oxidized in the human body, is capable of 
producing an amount of force equal to 1333 tons raised one foot 
high ; the dynamic value of wheaten flour, according to Frankland, 
is 2383 foot-tons; the great difference between these figures is of 
course owing to the large percentage of water in bread. It is 
instructive here to compare the dynamic value of some other 
well-known foods, z.e. the amount of energy that 1 lb. will yield: 
that of pea meal is 2341 foot-tons ; fish (mackerel), 1000; potatoes, 
618; milk, 390; egg (hard-boiled), 1415; lean of beef, 885; beef-fat, 
5640; butter, 4507 ; the high dynamic value of the last two articles of 
food being due to the superior heat- or force-producing power of 
fat, as compared to starch. But when we take into account the 
cost of these various articles of food, we find that for a given ex- 
penditure of money a larger amount of force or energy can be 
obtained from the cereal grains than from any other kind of food. 
For example, to raise 140 lbs. to the height of 10,000 ft., 1 lb. of pea 
meal would be required, costing 4d.; or of butter, } lb.=7d.; or 
potatoes, 5 lbs.= 3d. ; or mackerel, 3 lbs.=15. 7d¢.; or milk, 64 pints 
=I5s. 1d; or beef-fat, 4 lb.=4$d.; or lean of beef, 33 lbs. =35. ; or I 
