There are many complex dried foods in market prepared especially for invalid diet, and supposed to possess high nutritive value with small bulk. As compared with fresh food, their lighter weight and greater concentration make them valuable articles for temporary invalid diet, but they cannot be said to possess any special advantage over freshly made broths, scraped beef, etc., excepting in those cases in which it is important to lessen the bulk and increase the strength of the food.

Attempts have from time to time been made in the German army and elsewhere to supply healthy men with a daily diet of concentrated foods. If this could be done, it would be of great economic advantage for troops on the march, explorers in unknown countries, sailors on long voyages, and for use in many ways, but after a few days or a week of such treatment men lose in weight and deteriorate in strength. It is not found practical to give food for any length of time in which the total solid ingredients are concentrated to less than twenty-two or twenty-three ounces for the day's ration, although for a few days food may be used in which they have been reduced to ten or twelve ounces (Parkes). Pea meal (p. 167) and pemmican (p. 200) are the most noted rations of this class, to which bacon, hard-tack, concentrated meat extracts, coffee, and chocolate are often added.

In a series of very instructive and important articles upon Military Food, published in the Journal of the American Cavalry Association, Major Woodruff says: "Concentration only means the exclusion of the indigestible portions and part of the water. Thus the garrison ration gives to each man about five pounds of food, of which only four pounds are eaten, and it is impossible to condense this amount so that it will be much less than three pounds. All foods that are compressed and dried still contain from 5 to 12 per cent of water. The German soldier's war ration is equivalent to about two pounds of water-free food in the above sense. This is not enough for American soldiers during hard work, yet it is possible in an emergency to give the soldier fairly good nourishment with these improved foods, and not allow the weight to be over two pounds, as seen in the following table, in which the analyses are only approximate:

GRAMMES.

Articles.

Protein.

Fats.

Carbohydrates.

Salts.

Calories.

Weights.

3 cubes dried compressed bread, pound each.....

35

4

250

2

1.233

pound.

3 packages compressed soup,

6 ounces each

100

150

200

28

2,625

1 1/8 "

3 tablets compressed tea or coffee ready for use, possibly a tablet of dried fruit..

• • •

• • •

• • • •

1/8

Total.................

135

154

450

30

3,858

* 2 pounds.

* Gross weight.

"The composition of the bread is assumed to be the same as ordinary flour, and the tablets of soup can be manufactured of the given composition. As usually made, the tablets do not contain so much fat, which is here purposely increased in order to give the necessary energy. Even with this increase they would not contain as much as the first specimens of Erbswurst.

"For purposes of detached service the United States soldier has been supplied, as seen in the following table:

GRAMMES.

Articles.

Protein.

Fats.

Carbohydrates.

Salts.

Calories.

Weights.

1 pound hard-tack

50

5

340

2

1,644

I pound.

pound bacon

27

236

...

8

2,3I0

"

Coffee, sugar, and salt...

19

Total

77

241

340

30

3,954

2 pounds".