1881 .] 
AMERICAN AGRICULTURIST. 
511 
analyses, by Dr. Vcelcker and Dr. Frankland 
of the drainage waters, furnished by Drs. 
Lawes and Gilbert from the permanent ex¬ 
periment plots at Rothamsted, show that 
Nitrogen, in the form of Nitric Acid, is lost 
to a greater or less extent by leaching through 
the soil. During the period of the active 
growth of the crops, the waste of the Nitro¬ 
gen in the drainage water was slight, but in 
the interval that elapsed between the annual 
crops the loss of Nitrogen was much increased. 
The decomposition of the organic matters 
of the soil seems to be constantly going on, 
and the Nitrogen which is thus liberated in 
an available form for plant growth, is taken 
up by the roots of the crops during their 
period of growth ; but when there are no live 
roots in the soil to make use of this gradual 
and constant supply of available Nitrogen, it 
is carried out of the reach of growing plants, 
and lost in the drainage water. As a matter 
of economy in the conservation of this valu¬ 
able element of fertility, it would then be 
best to arrange the crops in rotation so that 
the soil, as far as possible, would be con¬ 
stantly occupied with the roots of growing 
crops. As rye continues its growth late in 
the fall, and starts again early in the spring, 
its value as a soiling crop, to fill up the in¬ 
terval between two annual grain crops, will, 
from this point of view, be readily recognized. 
In following out the indications of the 
facts we have presented, by keeping the land 
constantly occupied with profitable crops, 
care must be taken to secure time for the 
thorough preparation of the soil for each 
crop. For instance, wheat should not follow 
corn, as the seeding of the one interferes 
with the harvesting of the other, and the 
work is likely to be crowded and hurried, 
and in both cases imperfectly done. An in¬ 
tervening oat crop will give time for a thor¬ 
ough preparation for the wheat crop. 
The Value of Fish as Food. 
BY PROF. W. O. ATWATER, WESLEYAN UNIVERSITY, 
MIDDLETOWN, CONN. 
The flesh of fish is very much like that of 
warm-blooded animals. To the epicure it is 
often more dainty, while the poor man can 
buy nutritive materials in dried and salt fish, 
and often in fresh fish likewise, for only a 
fraction of their cost in ordinary meats. 
In general, fish has somewhat more water 
and less solids than beef, pork, mutton, and 
other common meats. But the solids, the ac¬ 
tual nutrients in the flesh of fish, consist of 
essentially the same kinds of substances as 
those of butcher’s meats. The proportions of 
the nutrients vary, and with them the nutri¬ 
tive values vary also. The composition and 
nutritive values of fish have, until lately, been 
but little studied. We know, in a general 
way, that some fish seem to make a very j 
substantial, and others only an inadequate 
diet; that salmon are more nutritious than 
cod, and fat fish more so than the lean and out 
of condition. But we need to know more 
definitely the nutritive values of different 
kinds of fish, and how they compare in this 
respect with each other and with other foods. j 
Under the auspices of the Smithsonian In¬ 
stitution, and the U. S. Fish Commission, an 
investigation of the chemistry and economic 
values of American food-fishes has been go¬ 
ing on for some time past, in the Chemical 
laboratory of Wesleyan University, the de¬ 
tailed results of which are to appear in the ! 
Report of the U. S. Fish Commission. Fifty- 
three samples of fishes and twenty-five of in¬ 
vertebrates, oysters, clams, lobsters, etc.,have 
already been analyzed. Some forty analyses 
have also been made and reported in Europe. 
Materials of which Fish are Composed. 
Considered from the stand-point of the food- 
value, fish, as we buy them in the market, 
consist of (1) Flesh, or Edible Portion, and (2) 
Refuse—bones, skin, entrails, etc. The pro¬ 
portion of refuse in different kinds of fish, 
and of different samples of the same kind, in 
different conditions, vary widely. Thus a 
sample of flounder contained 68 per cent of 
refuse and only 32 per cent of flesh, while 
one of halibut steak had only 18 per cent of 
refuse and 82 per cent of edible materials. 
Among those with the most refuse and least 
edible flesh are the flounder, porgy, bass, and 
perch. Among those with the least refuse 
are fat shad, fat mackerel, salmon, and dried 
and salt fish. 
The edible portion consists of (1), Water, 
and (2) Solids, actual nutrients. The propor¬ 
tion of water and solids in the flesh of vari¬ 
ous kinds of fish are much more variable than 
most people would suppose. Thus the flesh 
of flounder had 85 per cent of water and only 
15 per cent of solids, while that of salmon 
contained 36‘/ 2 per cent solids and 63'A per 
cent water, and the flesh of dried, smoked 
and salt, fish have still less water. Lean 
beef contains, on the average, 25 per cent, or 
one quarter its weight of solids, the other 
three-quarters being water, while fat pork 
has one half solids. Ordinary fresh meats 
are from one-half to three-fourths water, 
while the water in fresh fish varies from 
three-fifths to six-sevenths of the whole. 
To find the actual nutritive materials of 
a sample of fish, we must first substract the 
refuse, the entrails, bones, etc., which leaves 
the flesh. Then we must allow for the water 
in the flesh. What remains will be the total 
edible solids, the actual nutritive material. 
The percentages of edible solids in the differ¬ 
ent samples of fish were more varied than 
those of refuse and water. Thus 100 lbs. of 
flounder contained only 5 lbs. of actual nutri¬ 
ents ; 100 lbs. of haddock, 9 lbs. ; of bluefish, 
11 lbs. ; of cod, 12 lbs. ; salt mackerel, 16 
lbs.; shad, 16 lbs. ; salt cod, 20 lbs. ; salmon, 
27 lbs., and smoked herring, 28 lbs. 
The Nutrients oi Foods. 
The value of fish as food, like that of meats 
in general, is determined not only by the total 
edible solids, but by their ingredients. Leav¬ 
ing out of account the mineral substances 
and certain compounds which occur in 
small quantities, the most important ingredi¬ 
ents may be divided into three classes, the 
albuminoids, the carbohydrates, and the fats. 
Albuminoids, Carbohydrates- and Fats. 
Wheat gluten, the white (albumen) of eggs, 
curd of milk, and lean meat, are familiar ex¬ 
amples of albuminoid substances. Vegetable 
oils, such as linseed oil and olive oil, lard, 
tallow, and butter, are fats. Sugar, starch, 
and cellulose (woody-fiber) are carbohy¬ 
drates. The albuminoids are characterized by 
containing the chemical element, Nitrogen, 
of which the carbohydrates and fats are 
destitute. That is, the carbohydrates and 
fats consist of Carbon, Hydrogen, and Oxy¬ 
gen, while the albuminoids contain these and 
Nitrogen also. The carbohydrates serve chief¬ 
ly for fuel, to keep the body warm, and proba¬ 
bly to supply force, muscular strength. The 
fats are likewise used for fuel, but they also 
help to build up the fatty tissues of the body. 
The albuminoids are transformed into fats 
and into carbohydrates, and thus do the 
work of both these, but besides this they 
make the nitrogenous tissues of the body, 
the muscle, cartilage, etc., which the carbo¬ 
hydrates cannot do, because they have no 
Nitrogen. With albuminoids alone we might 
maintain life a good while ; on a diet of car¬ 
bohydrates and fats we should soon starve. 
The albuminoids are the most valuable of 
the nutrients of our food. Next in value come 
the fats, and last the carbohydrates. The fats 
are superior to the carbohydrates because 
they have more Carbon to serve as fuel, and 
because of their usefulness in forming the 
fats of the body. When-we know the chemi¬ 
cal composition of a food, we can compute 
with tolerable accuracy its nutritive value. 
Fish, like most other animal foods, consist 
mainly of albuminoids, with more or less of 
fats, and very little of the carbohydrates. To 
tell their relative values, we must compare 
their proportions of these ingredients. This 
is done in the following table, in which one 
pound of albuminoids is estimated as equiva¬ 
lent to three pounds of fats and five of carbo¬ 
hydrates. For the sake of comparison the 
composition and valuations of several other 
sorts of animal food are given with those of 
fish. The figures for meats, game, fowl, milk, 
eggs, etc., are from European sources. The 
relative valuations are given, medium beef 
being taken as the standard, and rated at 100. 
The figures apply to the flesh free from bone 
and other waste. They show the percentages of 
water, albuminoids, carbohydrates, and fats, 
the mineral matters being left out of account. 
NUTRIENTS AND VALUATIONS OF ANIMAL 
FOODS. 
FLESH. 
FREE FROM BONE AND 
OTHER REFUSE. 
Water. Per cent. 
j Albuminoids. 
Protein. Percent. 
1 
8 
Carbohydrates. 
■Pi 
■S 
Ag 
Meat. 
. 
76.7 
20.6 
1.5 
91 
“ medium. 
72.3 
21.4 
5.2 
100 
54.8 
16.9 
27.2 
112 
Veal “ . 
72.3 
18.9 
7.4 
92 
76.0 
18.1 
5.8 
87 
47.4 
14.5 
37.3 
110 
47.7 
27.2 
15.3 
140 
28.0 
24.0 
36.5 
157 
TTpt> . 
70.0 
18.5 
9.3 
94 
Milk. Eggs, Me. 
Cow's Milk. 
87.4 
3.4 
3.7 
4.8 
24 
“ “ skimmed.. 
90.6 
3.0 
0.8 
4.8 
19 
u “ cream. 
66.4 
3.7 
25.7 
3.5 
56 
Butter. 
14.1 
0.9 
83.1 
0.7 
124 
Cheese, skimmed milk. 
48.0 
32.6 
8.4 
6.8 
159 
“ whole milk .... 
46.8 
27.6 
20.5 
1.9 
151 
“ very fat.. 
35.7 
27.1 
30.4 
2.6 
163 
73.7 
12.5 
12.1 
72 
Fish {fresh). 
Halibut. 
74.3 
18.2 
6.5 
88 
83.8 
14.2 
0.7 
62 
Cod. 
82.7 
15.6 
0.3 
68 
81.2 
17.2 
0.2 
75 
75.8 
18.8 
3.9 
87 
70.5 
18.8 
9.8 
96 . 
68.1 
18.8 
11.7 
98 
78.9 
17.9 
2.1 
80 
77.8 
19.7 
1.0 
. 
87 
72.3 
18.3 
8-2 
91 
78.1 
19.3 
1.2 
85 
63.5 
19.7 
15-7 
108 
“ Trout. 
66.8 
17.2 
14.8 
96 
Whitefish. 
70.1 
22.1 
6.2 
105 
76.1 
20.9 
2.8 
94 
Red Snapper. 
76.7 
20.5 
1.3 
91 
79.7 
16.4 
1.9 
74 
07.7 
21.3 
9.4 
106 
75.5 
19.3 
4.0 
89 
67.7 
19.4 
11.4 
100 
70.1 
14.5 
14.1 
S4 
Prepared Fish. 
Boned Cod. 
'52.6 
24.6 
0.4 
107 
Salt “ . 
53.6 
23.5 
0.6 
' 
102 
Dried “ . 
18.6 
78.9 
0.8 
. 
3-11 
50.8 
18.4 
15.6 
. 
102 
Smoked Herring . 
35.7 
31.5 
18.6 
163 
Canned Salmon. 
66.0 
21.1 
11.1 
107 
Salt Mackerel. 
44.7 
17.7 
23.9 
111 
