is the shad. It is found along the whole Atlantic coast, coming into
fresh water for spawning, where it is caught for food purposes. The
shad begin to appear in the streams of the south Atlantic coast early
in the winter and as the spring advances they go northward. They
appear in the Potomac in April and May, and later in the Delaware and
Connecticut rivers and other fresh-water streams further north. The
fish is, therefore, to be had fresh upon the market over a long period
of time. The common shad is known scientifically as _Alosa sapidissima_
(Wilson). As a result of the work of the U. S. Bureau of Fisheries
the shad has been introduced into the waters of the Pacific coast
where none was found originally. The shad fry were first introduced
into the Sacramento river and afterward into the Columbia river. The
environments on the Pacific coast were found congenial. The fish soon
found grounds on which they could spawn, and they have spread over
almost the entire length of the Pacific coast. It has, of late, become
a very common and abundant food fish on the Pacific coast and has lost
none of its palatability by transplanting. Science has not been able to
ascertain anything of very great interest respecting the life of the
shad in the sea. When they leave the rivers they practically disappear,
and are not known again until the next spawning season returns. For
spawning purposes the shad prefer a water temperature of from 55 to 65
degrees. Whenever the temperature goes above the latter figure they
begin to disappear. The males and females go in separate schools. The
males usually precede the females. It is stated by Jordan and Evermann
that of 61,000 shad received at the Washington market from March 19 to
24, 99 percent were male. As the season advanced the males became very
much less frequent and at the end extremely scarce. The U. S. Bureau of
Fisheries has taken especial pains to increase the number of shad in
all waters. During the spring of 1900 there were artificially planted
in the Atlantic coast streams over 240,000,000 young shad. One fish
often contains as many as 150,000 eggs. The average number, however, is
about 30,000. Shad roe is the most valuable part of the fish and brings
a much higher price in the market than an equal weight of fish itself.
Planked shad is one of the greatest delicacies of the Washington
markets. At Marshall Hall, opposite Mount Vernon, there are given a
great many shad bakes during the season. Oak wood is placed in long
lines and burned,--oak planks are set up on each side of the line of
burning wood, inclined at an angle of about 60 or 70 degrees. On these
oak planks the shad are cooked, held usually by driving a nail through
the head,--the cut surface being exposed to the heat of the burning
fire. In addition to being cooked in this way the fish absorbs a small
amount of the empyreumatic odors of the burning wood. During the baking
the shad are treated from time to time with melted butter. There is no
other way which a shad can be cooked which renders it so delicious as
by this primitive method. The shad, from an economic point of view, is
third in importance in the United States, only the salmon and the cod
exceeding it in value. The annual catch of shad on the Atlantic sea
coast numbers from 10 to 20 million, weighing from 40 to 60 million
pounds and worth from one and one-half to two million dollars.
_Composition of Shad._--
FRESH. DRY.
Water, 70.62 percent
Protein, 18.56 „ 64.36 percent
Fat, 9.47 „ 31.93 „
Ash, 1.35 „ 4.62 „
Of the whole weight of shad the average edible portion amounts to 52.35
percent, and the refuse, counting the bones, skin, and entrails is
47.65 percent.
_Shad Roe._--The eggs of shad, as has already been mentioned, are
regarded as the most valuable portion of the fish. Roe shad also are
more highly prized as a food fish than the male shad. As a result, roe
shad sell for a much higher price on the market than the male shad. The
eggs are quite small, and as has already been said, occur in immense
numbers, the average number to a fish being about 30,000.
_Composition of Shad Roe._--
Water, 71.2 percent
Protein, 23.4 „
Fat, 3.8 „
Ash, 1.6 „
Aside from the water of the roe, it is noticed that by far the most
abundant component is the protein. This, of course, is what would be
expected of an egg product. The protein is a little more than six times
as great as the fat. The ash contains large quantities of phosphorus,
which exists in the original egg, largely in the form of lecithin,
in which state it is regarded as most valuable for nourishing the
phosphatic tissues of the body. Shad roe is eaten almost entirely in
the fresh state. It does not produce a pickled or cooked product of
anything like the value of the sturgeon eggs. So far as the author
knows no form of shad egg preparation similar to caviar is on the
market.
There are three species of shad in America, but the only one of great
importance is the common Atlantic shad which has been described.
=The Sheepshead.=--This abundant and important food fish exists in
large numbers along the Atlantic coast. It also belongs to the Sparidæ
and its scientific name is _Archosargus probatocephalus_. This species
is found from Cape Cod to Texas. It is especially found in the vicinity
of oyster beds, where it is destructive to the oysters. It is quite
abundant in the Indian river, being, next to the mullet, the most
frequently found fish in those waters. Though strictly a salt-water
fish, it often runs up into fresh waters. The fish is distinguished by
the number of broad silvery colored bands extending around its entire
body. The average weight of the sheepshead is three or four pounds,
though occasionally a fish three or four times that size is captured.
_Composition of Sheepshead._--
FRESH. DRY.
Water, 75.55 percent
Protein, 19.54 „ 83.47 percent
Fat, 3.69 „ 13.59 „
Ash, 1.22 „ 5.14 „
=The Smelt.=--The smelt belongs to a family which has a number of
species, some of which are very abundant in Europe, where they are
highly prized even to a greater extent than in this country for food.
The smelt is a small fish, very long in proportion to its breadth.
The American smelt (_Osmerus mordax_) is found very abundantly on the
Atlantic coast north of New York. Although a sea fish, it often enters
rivers and becomes landlocked in lakes. It is found abundantly in Lakes
Champlain and Memphremagog and many of the New England and Nova Scotian
lakes. The smelt in early times was a very abundant fish.
_Composition of the Smelt._--Edible portion:
FRESH. DRY.
Water, 79.16 percent
Protein, 17.37 „ 84.31 percent
Fat, 1.79 „ 8.65 „
Ash, 1.68 „ 8.16 „
These data show that the flesh of the smelt is very rich in protein,
the fat falling to a very small proportion of the total edible
substance.
=Spanish Mackerel.=--This is a very highly prized fish and is eaten
largely in the fresh state along the Atlantic coast. Its scientific
name is _Scomberomorus maculatus_. The catch is subject to great
variations. In early years the Spanish mackerel was scarcely known on
our coast, but in the last forty years it has assumed considerable
importance. Although more abundant than formerly it still commands a
very high price. The weight of the full-grown mackerel is usually from
five to eight pounds, though occasionally very large individuals are
taken. Jordan and Evermann speak of one which was 41 inches long and
weighed 25 pounds.
_Composition._--Edible portion:
FRESH. DRY.
Water, 68.10 percent
Protein, 20.97 „ 67.25 percent
Fat, 9.43 „ 29.56 „
Ash, 1.50 „ 4.71 „
In this fish it is seen that the fat is a little less than one-third
the quantity of the protein.
=Sturgeon.=--The sturgeon belongs to the family of Acipenseridæ.
They are large fishes frequenting the sea and also the fresh waters
of northern regions. Most of the species are anadromous, entering
fresh water and ascending the streams in spring. There are two genera
belonging to this family and 20 species that are well defined, although
about 100 nominal species have been described. The white sturgeon or
Oregon sturgeon is found on the Pacific coast from Monterey north to
Alaska. It ascends the large rivers during the spring, notably the
Sacramento, Columbia, and Fraser rivers. Some of them are very large
and their value for food and commercial purposes has only been lately
recognized. They are principally valuable, however, for their eggs or
roe, since it is from the eggs of sturgeon that caviar is made. The roe
in the fresh state is worth from 25 to 30 cents a pound. The fresh fish
are frozen and shipped to Eastern markets.
The common sturgeon (_Acipenser sturio_) frequents the east and north
Atlantic coast and ascends the rivers in the spring, especially the
Delaware. The quantity of sturgeon taken, however, has constantly
decreased for several years. The principal part of the caviar made in
the United States is procured from the common sturgeon and the Lake
sturgeon, which is found in the Great Lakes, the upper Mississippi
Valley, and the Lake of the Woods.
_Preparation of Caviar._--After the eggs have been removed from the
fish, they are placed in large masses upon a stand, the top of which
is formed of a small-meshed screen. On the under side is placed a
zinc-lined trough, about 18 inches deep, 2 feet wide and 4 feet long.
The operator gently rubs the mass of eggs back and forth over the
screen, whose mesh is just large enough to let the eggs drop through
as they are separated from the enveloping membrane. They thus fall
into the trough from which they are drawn off into tubs through a
sliding door in one end of the trough. After all the roe has been
separated, the tub is removed and a certain proportion of the best
Luneberg salt is added and mixed with the eggs by careful stirring
with the hands. This is the most delicate part of the whole process,
and the best results can be obtained by that proficiency which comes
from long experience. After adding the salt, the eggs at first become
dry, but in 10 or 15 minutes the salt has drawn from the eggs their
watery constituents and a copious brine is formed, which is poured off
when the tub becomes too full. The salted eggs are then poured into
fine-meshed sieves which hold about 10 pounds each, where they are
allowed to drain for 8 to 20 hours. The eggs have now become the caviar
of commerce, which is put in casks or cans of various sizes.
_Composition of the Flesh of Sturgeon._--
FRESH. DRY.
Water, 78.71 percent
Protein, 17.96 „ 85.19 percent
Fat, 1.90 „ 8.90 „
Ash, 1.43 „ 6.72 „
_Composition of Caviar._--
Water, 66.05 percent
Protein, 14.37 „
Fat, 8.97 „
Ash, 7.26 „
Undetermined, 3.35 „
Of the ash, 6.16 parts of the 7.26 present are common salt.
=Composition of the Eggs of Fish.=--Attention has been called to the
valuable food properties of the eggs of fishes. The roe of a number
of fishes is celebrated both for flavor and food value. The two most
important roes are those of the sturgeon, used in the manufacture of
caviar, and the roe of shad, used principally in the fresh state.
=Composition of Roe.=--The composition of shad roe, fresh sturgeon
caviar, and pickled caviar is given in the following table:
---------------+---------+---------+---------+---------
| WATER. | PROTEIN.| FAT. | ASH.
---------------+---------+---------+---------+---------
|_Percent_|_Percent_|_Percent_|_Percent_
Shad roe, | 71.25 | 23.44 | 3.78 | 1.53
Fresh caviar, | 56.97 | 27.87 | 2.85 | 2.31
Pickled caviar,| 50.92 | 27.92 | 13.59 | 7.57
---------------+---------+---------+---------+---------
The above data show a marked difference between the composition of shad
roe and sturgeon roe, the latter being very much richer in fat and
also containing a greater quantity of ash. The large quantity of ash
in the pickled caviar is doubtless due to the common salt used in the
curing. There is not a very great difference between the composition
of the roe and that of the flesh of fish. The roe is essentially a
nitrogenous food, also with a considerable quantity of fat and with
a certain amount of mineral matter. It contains less water than the
flesh of fish, and, therefore, pound for pound in the fresh state has
a larger quantity of nutrients. Otherwise, for food purposes, there is
but little difference. It is doubtless true, however, that the mineral
matters of the roe are somewhat different from those of the flesh of
fish in containing a larger quantity of organic phosphorus in the form
of lecithin.
=Striped Bass.=--The striped bass or rock (_Roccus lineatus_) is a fish
of the family Serranidæ and quite common in the Potomac. It occurs
commonly around the Atlantic coast. Its scientific name is _Roccus
lineatus_. It is taken in all waters along the coast from the Carolinas
to New England, and especially near the mouth of the Potomac and in
Chesapeake Bay. It is a fairly common as well as one of the best food
fishes at Washington and in many of the fish markets on the Atlantic
coast.
FRESH. DRY.
Water, 77.70 percent
Protein, 18.31 „ 83.28 percent
Fat, 2.83 „ 12.50 „
Ash, 1.16 „ 5.22 „
=Sole.=--The term “sole” is applied here to certain species of
flounders and the two terms are sometimes used synonymously. The
true soles, however, of which there are several species, belong to a
distinct though closely related family. The species of flounder to
which the term “sole” is generally given is _Eopsetta jordani_. It
occurs along the Pacific coast from Monterey to Puget Sound. Large
numbers are taken in Monterey Bay. The average weight of this “sole”
is about three pounds. It is highly esteemed as a food fish. They are
dried in great numbers by the Chinese, who suspend them by strings on
a frame placed on the roofs of the houses, where, after they become
dry, they strike against each other when moved by the wind, producing
a sound which is something like that emanating from the leaves of a
forest.
=Tautog.=--The _Tautoga onitis_ is one of the wrasse-fishes (family
Labridæ) and is abundant along the Atlantic coast from New Brunswick to
the Carolinas. East of New York it is commonly called the “tautog.” On
the New York coast it is known as “blackfish,” and further south as the
“oyster fish.”
=Tilefish.=--The tilefish is interesting not because of its high food
value but because of the fact that it was discovered by accident in
1879 when a fisherman off the coast of Nantucket captured 5000 pounds
of a fish which was new to him. The species was also new to science.
This fish disappeared as suddenly as it came and no more were caught
until 1892. Since then they have been taken rather frequently. The
tilefish reaches a length sometimes of three feet and a weight of 30
pounds. It is pronounced by experts to be the equal of the pompano.
=Trout.=--Trout, of which there are many species, are greatly prized
both on account of their value as game fishes, affording sport for
anglers, and because of their high palatable qualities. They belong
to the same family as the Atlantic salmon and often it is difficult
to distinguish by any of its common characteristics a trout from a
salmon. This is especially true of trout of western America. The
species of trout which are most highly prized on the Pacific coast
are the cut-throat trout (_Salmo clarkii_), the rainbow trout (_Salmo
iridens_), and the steel-head (_Salmo gairdneri_). The familiar silver
trout of Lake Tahoe is another closely related species. They are
distinguished by a remarkable system of spots of a circular form, black
in color, and of varying size. The Lake Tahoe trout which is commonly
secured is not the same as the silver trout of Lake Tahoe but is of a
little different character, and is also known as the Truckee Trout,
“Pogy,” and “Snipe.” It reaches a weight of from three to six pounds
and is sometimes served on the dining cars of the Central Pacific
Railway, in running through Idaho and into California. Various other
species of the trout are found in Utah, in the Rio Grande and the
Colorado, and in the lakes of Colorado. Perhaps the most important of
these is the steel-head trout occurring along the Pacific coast. The
rainbow trout is also a fish that is highly prized along the Pacific
coast. The brook trout of western Oregon is also an important fish.
_The Trout of the Great Lakes._--The fish known as trout in the Great
Lakes belong to a different genus from those already mentioned, namely,
genus _Cristivomer_. It has, however, the typical spots, which are of
a grayish color instead of red or black like those of the other trout
which have been mentioned.
The principal species which abounds in the Great Lakes is the Mackinaw
trout (_Cristivomer namaycush_). It is also found in the large lakes
from Maine westward to the Pacific ocean and even to northern Alaska.
This is the largest species of trout. The average weight of the fish
probably does not exceed 15 or 20 pounds. Individual examples have been
found weighing over 100 pounds. There is only one common fish which
exceeds it in weight, namely, the sturgeon. Next to the white fish it
is the most important commercial fish of the Great Lakes. The supply of
lake trout has been diminishing and the price increasing for several
years. The spawning season of lake trout begins in September and
continues until December.
_Composition of Lake Trout._--
FRESH. DRY.
Water, 69.14 percent
Protein, 18.22 „ 60.10 percent
Fat, 11.38 „ 36.80 „
Ash, 1.26 „ 4.90 „
_Composition of Brook Trout._--
FRESH. DRY.
Water, 77.72 percent
Protein, 18.97 „ 86.62 percent
Fat, 2.10 „ 9.16 „
Ash, 1.21 „ 5.39 „
The above data show that lake trout has a flesh which approximates in
composition that of Pacific salmon, being quite rich in fat, while the
brook trout has a composition more like the Atlantic salmon, being
very rich in protein and poor in fat. Trout of all kinds are used
practically in only a fresh state. The catch is not large enough to
warrant the establishment of canning factories and all that are caught
in the northern and central northern lakes and streams find a ready
market in a fresh state at much more remunerative prices than could be
obtained by canning. It is always a fortunate circumstance when the
condition of the catch and of the market are such as to enable the fish
to be eaten as fresh as possible from the water. Fish is a kind of food
which is never improved by keeping in any way and is at its best the
minute the fish is taken from the stream. The brook trout do not belong
to the same genus as the lake trout but to the genus _Salvelinus_.
They have a general resemblance, however, to that genus. As a fish to
be caught by the hook and as a victim of sport the brook trout perhaps
occupies the highest place among the fish of the country; especially
is it sought for in the mountain streams, and it occurs in most parts
of the northeastern United States. It extends from Maine to northern
Georgia and Alabama, especially in the Appalachian Mountains and west
through the Great Lakes to the Mississippi, while in Canada it is found
from Labrador to the Saskatchewan.
The brook trout has been especially cultivated by the U. S. Bureau of
Fisheries and introduced into waters in the United States where it is
not found naturally. The season for spawning for the brook trout is in
the autumn, when the water is growing colder, and continues from August
to December, according to the latitude. In spawning time the fish come
up into the smallest parts of the stream where shallow water can be
found. The eggs remain until the next spring, when they are hatched.
The brook trout varies greatly in size, according to the magnitude of
the stream. In the small streams it weighs often less than ¹⁄₄ pound,
while in large streams it weighs 2 or 3 pounds. The large trout has
almost disappeared from the small streams as a result of the activity
of fishermen.
There are many other species of trout which are known in different
parts of the country. For instance, the Dublin Pond trout of Dublin
Pond, N. H., the Dolly Varden trout in the northern Pacific states and
Alaska, the Sunapee trout in the northeastern states, and the Blueback
trout in Maine. These fishes all have practically the same quality,
varying only in minute details, and have the same value as a food.
=Turbot.=--A species of halibut known as Greenland halibut
(_Reinhardtius hippoglossoides_) is also known as turbot in this
country. It occurs chiefly off the coast of Greenland, and is taken
in the very coldest part of the year. The European turbot is _Psetta
maxima_.
=Weakfish.=--The weakfish belongs to the croaker family (Sciænidæ)
and has a high value as a food fish, the flesh being rich in flavor
and very tender and easily disintegrated, from which quality it is
believed the name “weakfish” is derived. The common weakfish is the
species _Cynoscion regalis_. It is also known in some localities as
the squeteague. The fish is rather long in proportion to its breadth
and sometimes grows to a large size. Examples weighing over 25 pounds
have been captured. Very rarely, however, does a weakfish weigh more
than 10 pounds, and the average is perhaps not more than one-half that.
The weakfish is, particularly when young, a victim of the bluefish,
and great numbers succumb to the ravages of its more powerful enemy.
The weakfish is found over the entire length of the Atlantic and Gulf
coasts as far north as the Bay of Fundy. The weakfish sometimes ascends
the tidal waters and congregates around the river mouths, where the
food is more abundant. While found on the markets in the North, it is
more highly prized in the southern markets.
_Composition._--
FRESH. DRY.
Water, 78.97 percent
Protein, 17.45 „ 84.63 percent
Fat, 2.39 „ 11.37 „
Ash, 1.19 „ 5.64 „
The flesh of the weakfish, as shown by the above data, is one in which
the protein exists in very much greater proportion than the fat. It is
not so rich in protein, however, as some of the other species which
have been mentioned.
=Whitefish.=--This fish occurs in large numbers in all our Great Lakes,
and is an abundant article of food. Its scientific name is _Coregonus
clupeiformis_. It inhabits the whole of the Great Lakes regions from
Lake Champlain to Lake Superior. It does not occur in very great
abundance, if at all, west of Lake Superior, although it has been
reported to have been found in the fresh water lakes both to the north
and west of that region.
The common whitefish prefers the deep water of the lakes, coming
only into shallow water near the shore at spawning time, which, in
the Great Lakes, is from October to December. During the months of
January, February, and March the fishing for whitefish is practically
discontinued, since the fish at that time have returned to deep water
and are not accessible.
The size of the whitefish in the Great Lakes is not so great as
the extent of water would indicate. Probably three pounds would be
an average size, although the individual fish range from 1¹⁄₂ to 6
pounds. The weight rarely, however, exceeds 4 or 5 pounds. Occasionally
whitefish have been found weighing as high as 20 pounds, but this is
very rare. The whitefish reaches its full average size about the end
of the fourth year. The number of eggs which are found in the female
fish is not so large as in the shad, but usually the number does not
fall below 10,000 and sometimes reaches as high as 75,000. The eggs are
very small comparatively, and about 36,000 of them make a quart. The U.
S. Bureau of Fisheries has done a great deal to increase the supply of
whitefish by planting millions of whitefish fry in suitable water.
_Different Species of Whitefish._--There are many species of whitefish
besides the common whitefish which appear in the Great Lakes. Coulter’s
whitefish is found in the waters of British Columbia, but it is not
distributed very widely throughout the country. The Rocky Mountain
whitefish is very widely distributed, occurring in all suitable waters
from the west slope of the Rockies to the Pacific. There is also a
subspecies of this fish occurring in the headwaters of the Missouri
river. Menominee whitefish occur in the lakes of New England, New York,
and the Great Lakes,--it is also known as round whitefish, frostfish,
shadwaiter, pilotfish, chivey, and blackback.
_Composition of Whitefish._--
FRESH. DRY.
Water, 69.83 percent
Protein, 22.06 „ 76.00 percent
Fat, 6.49 „ 21.51 „
Ash, 1.62 „ 5.36 „
_Average Composition of Fish._[16]--
Water, 76.06 percent
Solids, 23.94 „
Nitrogen, 3.51 „
Phosphoric acid, .52 „
Sulfur, .24 „
Fat, 1.45 „
Ash, 1.21 „
Protein, 21.92 „
[16] Average analysis of cod, halibut, bass, etc., used at the
hygienic table of the Bureau of Chemistry.
=Fluorids in Fish.=--Nearly all kinds of fish yield a distinct test
for fluorin which is not to be mistaken for an adulteration. The
fluorin is found normally in the bones of the fish and sometimes in
traces in the flesh. The addition of fluorid as a preservative is
highly reprehensible, and its presence is indicated by the increase in
quantity.
=Marketing of Fish.=--In the food act it is provided that no animals
shall be used for food which have died otherwise than by slaughter.
Whether or not this would apply to fish is a matter of some doubt.
Unfortunately fish, as a rule, are allowed to die by being deprived of
oxygen, which they get from the water as it passes over their gills.
The common practice is to take the fish for commercial purposes in
seines or other gear and allow them to die, as it were, by suffocation.
The greater number of fish exposed upon our markets have died in this
way and are then packed in ice and kept until sold. The ideal way
to treat fish would be to transfer them from the seine to a pool of
water, fresh or salt, in which they are kept alive until they are
wanted for cooking. This method is practiced in some very high-grade
restaurants and hotels where the diner may pick for himself from the
pool the fish he desires to eat. It is evident that for commercial
purposes where a cheap food is desirable a method of this kind could
not be practiced. It is a question which the hygienist as well as the
practical man should consider, that is, whether or not it is possible
to slaughter the fish and, as soon as they are taken, dress them, pack
their carcasses in ice, and in this way deliver them to the markets.
Where fish are used for canning or salting purposes they are often
slaughtered as soon as caught. This is particularly true of herring
captured in the Potomac and Susquehanna rivers. It is an interesting
problem to study whether or not the flavor and character of the flesh
are impaired by the suffocation process subsequent to their capture.
In all cases except in cold weather, the fish after capture, no matter
whether they are allowed to die by suffocation or slaughtered, should
be packed in ice and kept until the market is reached, which should be
at as early a date as possible. Fish are never so good as when fresh
and the fresher the better.
=Cold Storage.=--Fish is a product which is often found in cold storage
in large numbers and kept there for a long time. The usual problem
attending the cold storage of food is even more important when
applied to fish. In cold storage fish are frozen solid and kept in
this state until ready for consumption. Just how long the palatability
and wholesomeness of fish can be preserved when frozen solid has not
been determined. It follows logically that the colder the temperature
the less the degree of deterioration, but it does not follow logically
that this temperature can be maintained indefinitely without injuring
the character of the product. One thing appears to be certain, namely,
that the consumer is entitled to know whether in any given case the
fish he purchases is a fresh or a cold storage article. At the present
time, in so far as I know, there are no national, state, or municipal
laws whereby this fact can be ascertained. Without raising the question
of comparative value or palatability there is no doubt but what the
consumer is entitled to know the character of the fish he purchases.
=Canning Fish.=--Allusion has already been made to the practice of
canning fish, especially salmon. Great precautions must be used in
cases of this kind, since fish is a food which tends to develop
poisonous principles incident to decomposition. Canned fish, therefore,
must be thoroughly sterilized so that no fermentative action tending to
produce ptomain poison can possibly take place. It should be the duty
of inspectors of food to frequently examine packages of canned fish to
determine, first, by the external appearance of the can, and, second,
by opening a certain number of them, whether any decomposition has
taken place. Too great care cannot be exercised in this matter, since
dangerous and often fatal results follow the consumption of spoiled
fish.
=Drying and Salting Fish.=--The preservation of fish by pickling,
salting, drying, and smoking is a great industry and produces some of
the most palatable products. Mackerel, herring, and cod are types of
fish which upon proper curing make a most delectable dish. Nothing but
encouragement should be given to industries of this kind, but in order
that they be of their true value they should be conducted properly with
due regard to hygienic principles and for the sole purpose of making a
wholesome and palatable product.
=Adulteration of Fish Products.=--Attention has already been called
to the adulteration of salmon by canning an inferior grade or even a
different kind of fish under the name of a better species. The same
remark may be made respecting all fish, hake, haddock, and cusk being
often offered as cod. In the case of sardines a similar practice is
in vogue, and the small herring which are captured off the coast of
Maine are often sold under the name of sardines. The substitution of
one variety of fish for another, however, is injurious only in the way
of fraud, the substitute fish presumably being of equal wholesomeness
to the other under whose name it is sold. On the contrary, the form
of sophistication which permits the introduction of deleterious
substances into fish food is highly objectionable from the dietetic
point of view. Following the general principles of nutrition, all
chemical, non-condimental preservatives are to be rigidly excluded
from fish products. This rule excludes boric acid, borax, benzoic acid
and benzoates, sulfites, formaldehyde, and all other forms of chemical
preservatives.
When fish are packed in oil the character of the oil used should
be made known to the consumer. Especially is this true if from the
locality where the fish is preserved and the general method of packing
the consumer is led to believe that a high-grade oil such as olive oil
has been used.
=Value of Fish as Food.=--From the statements which have been made
in connection with fish in particular and the analyses which have
been given it is seen that fish is a food of a peculiarly nitrogenous
character. The edible portions, exclusive of water, are at least
three-fourths, and probably more composed of protein. The other edible
nutritive product is fat or fish oil. The mineral nutrients compose
the remaining edible portion of fish after the protein and fat are
considered. The mineral portions of fish cannot be regarded as not
nutritious since they contain phosphoric acid and lime, which are
essential ingredients of food. The flesh of fish, however, as it has
been seen, is not a complete ration, but is lacking in carbohydrates,
and for this reason fish should be eaten with potatoes, rice, or other
highly starchy foods. The value of fish as a food is unquestionable and
its more general consumption would doubtless prove beneficial.
Those who live in the interior of large and extensive regions where
fresh water fish are not very abundant do not appreciate the value of
fish as food as do those who live upon the coasts washed by salt water
and near the interior fresh waters where an abundant supply of fish is
secured.
SHELLFISH.
=Clams.=--Clams are shellfish which, though not so extensively used as
the oyster, are valued food products. The clams of commerce are of two
kinds. The species known as long or soft clam is abundant on the New
England coast, and is of considerable commercial importance both fresh
and as a canned product. This is the clam used at clam bakes, for which
the New England coast is famous. Its technical name is _Mya arenaria_.
The other species, the round or hard clam, northward known as quahog,
is the most common clam of the markets south of New York. Its
scientific name is _Venus mercenaria_.
A very small round clam is known as the little neck. This has a flavor
which is extremely delicate and it takes the place, in the warm months,
of the blue point oyster on the menus of the hotels and restaurants.
The clam may be considered as a supplemental shellfish to the oyster,
being most delicious and most abundant during the closed oyster
season. The average weight of the round clam is about 60 grams, of
which about one-fourth is flesh, one-fourth liquid, and one-half shell
and refuse. There are many specimens very much larger than this but the
weight is given for those usually eaten.
_Composition of Clams._--Edible portion:
Water, 78.57 percent
Protein, 14.86 „
Fat, 1.78 „
Ash, 2.49 „
Undetermined, 2.30 „
The liquid which escapes upon the opening of the shell is composed
chiefly of water and salt and its composition is as follows:
Water, 96.02 percent
Protein, .65 „
Fat, None
Common salt, 2.81 „
Undetermined, .52 „
The flesh of clams, it is seen, is not very different from that of fish
in general. It is composed chiefly of water and of the nutrients the
protein is the predominating constituent. The ash content is somewhat
higher than is the case with fish.
If the flesh and fluid substance of the clam be considered together the
composition of the whole mass is represented by the following data:
Water, 86.11 percent
Protein, 8.71 „
Fat, 1.01 „
Ash, 2.63 „
Undetermined, 1.54 „
_Composition of Water-free Substance of the Flesh._--
Protein, 69.37 percent
Fat, 8.32 „
Ash, 11.64 „
Undetermined, 10.67 „
_Composition of the Dry Substance of the Liquid Portion._--
Protein, 16.37 percent
Fat, .10 „
Ash, 70.41 „
Undetermined, 13.12 „
_Composition of the Dry Substance of the Flesh and Liquid Together._--
Protein, 62.81 percent
Fat, 7.30 „
Ash, 18.92 „
Undetermined, 10.97 „
=The Lobster= (_Homarus americanus_).--The lobster is a crustacean
which occurs along the northern Atlantic coast. Formerly it was so very
abundant that it was almost a drug on the market. In the last quarter
of a century the increase in the consumption of the lobster has been
more rapid than the increased growth, so that the price has become
higher and higher; and this, to a certain extent, is limiting the
consumption. The coast of Maine is especially the fishing grounds for
the American lobster, though it is found much further south and also
in great abundance further north. The lobster varies greatly in size.
The law, at the present time, prevents very young lobsters from being
sent into commerce. They are usually from 10.5 to 15 inches in length,
though occasionally examples of enormous size are taken. The edible
portion of the lobster is the liquid and the flesh of the body, claws,
and tail. Only about one-half the weight of the lobster, including the
liquid, therefore, is edible. The rest is refuse. In a lobster weighing
a thousand grams (2.2 pounds), five hundred grams (1.1 pound) will be
the average edible portion, and the other half the refuse and loss.
The average lobster of the present day, perhaps, weighs scarcely two
pounds, though in former times the weight was very much greater because
the younger and smaller lobsters were not sent to the market. The color
of the lobster as it comes from the water is dark green, almost black
at times. Heat changes the color of the shell, so that after boiling or
baking the lobster becomes red. The flesh of the lobster is decidedly
sweet, owing to the large quantity of glycogen which it contains. There
is only one kind of meat that is eaten which approaches the lobster in
its content of glycogen, and that is horse meat.
_Composition of the Lobster._--Edible portion:
FRESH. DRY.
Water, 84.30 percent
Protein, 11.63 „ 74.06 percent
Fat, 1.82 „ 11.62 „
Ash, 1.63 „ 10.38 „
Glycogen, .62 „ 3.94 „
=Crabs.=--The crab is a shellfish very highly prized along the whole
of the Atlantic coast. Numerous species of crabs are used for food.
These are used in two forms--as hard-shelled or soft-shelled crabs. The
species most valued is _Callinectes hastatus_. It is very abundant on
the middle and south Atlantic coast. Crabs are quite abundant on the
Pacific coast also. About 44 percent of the total weight of the crab is
edible and 56 percent shell and refuse. In the edible portion about 77
percent is water and 23 percent solid matter.
_Composition of the Water-free Substance of the Crab._--
Protein, 72.56 percent
Fat, 8.55 „
Ash, 13.64 „
The flesh of the crab is, therefore, essentially a nitrogenous food,
containing only a small quantity of fat. A considerable portion of the
ash is common salt.
=Crawfish.=--The crawfish may be regarded as a fresh-water lobster. It
is found practically over the whole of the United States in the fresh
waters but is not used to any extent for food purposes, except on the
Pacific coast. It contains even a less proportion of edible matter
than the lobster. The refuse, shell, etc., form about five-sixths of
its weight. In the edible portion the water constitutes 81.22 percent,
while the solid matters are only 18.78 percent.
_Composition of the Water-free Substance of the Crayfish._--
Protein, 85.19 percent
Fat, 2.45 „
Ash, 6.98 „
=Canned Lobster, Clams, and Crabs.=--As in the case of oysters, there
is a large industry in the United States engaged in the canning of
the flesh of lobsters, clams, and crabs. The same precautions should
be observed in the eating of these canned products as those mentioned
in the case of salmon. Numerous instances of illness and sometimes of
death have been recorded as the result of eating these canned products
which have been imperfectly sterilized. When the flesh is canned
immediately after the capture of the animal, before any incipient
decomposition has taken place and when the sterilization is perfect,
the canned product can be eaten without fear. Where the health of the
people is so seriously involved, the factories where these products
are prepared should be carefully inspected either by the municipal,
state, or federal authorities. All material used in canning which is
not perfectly fresh from the water is to be rejected and the processes
employed in the preparation and sterilization must be those which will
effectively secure a complete immunity from subsequent fermentation and
the development of ptomain products.
_Composition of Canned Lobster (Dry Substance)._--
Protein, 81.46 percent
Fat, 4.64 „
Ash, 11.23 „
As seen from the above the composition of the dry substance in canned
lobster, except content of water, is not perceptibly different from
that of the fresh sample.
_Composition of the Dry Substance of Canned Crabs._--
Protein, 79.10 percent
Fat, 7.55 „
Ash, 9.68 „
=Shrimp= (_Crangon vulgaris_).--The shrimp is a highly valued article
of food, especially when it can be had fresh or properly canned. It
has been a practice to ship shrimps in bulk preserved with sulfites or
boric acid. This is a most reprehensible form of adulteration.
=Canned Shrimps.=--In the total dry edible portion, including solids in
the liquid contents of the can, are found:
Protein, 86.89 percent
Fat, 3.44 „
Crude ash, 8.84 „
In edible portion (flesh plus liquids):
Water, 70.80 percent
Water-free substance, 29.20 „
Protein, 25.38 „
Fat, 1.00 „
Crude ash, 2.58 „
Extractives, 0.24 „
Nitrogen, 4.06 „
Total edible portion, 100.00 „
The above data show that the shrimp in the canned state has less water
in it than in the fresh state, and contains one-fourth of its weight of
protein.
=Aquatic Reptiles.=--All forms of turtle may be used for edible
purposes, both of the fresh-water and salt-water species. Both the
turtle and terrapin are amphibious animals; that is, they can live
either in the water or on the land. Among the turtles the marine
variety known as the green turtle is most highly prized for food
purposes. Its Latin name is _Chelonia mydas_. It grows sometimes to an
enormous size, weighing several hundred pounds, and specimens weighing
50 and 100 pounds are not unusual. It is utilized chiefly for making
soup, and green turtle soup is considered of high quality by experts.
The flesh is also edible, and in the making of some varieties of green
turtlesoup pieces of the flesh are included.
_Composition of the Green Turtle._--The edible portion of the green
turtle has the following composition:
Water, 79.78 percent
Protein, 19.83 „
Fat, .53 „
Ash, 1.20 „
The edible portion of the green turtle is not very large in proportion
to its weight, as it forms only from 20 to 24 percent of the whole
weight of the turtle.
Among the reptiles there are several aquatic species which are used
as food. The most noted of these is the diamond-back terrapin, which
is found in the salt-water bays, lagoons, and marshes of our Atlantic
coast from New Jersey to Texas. Its center of greatest abundance is
in Chesapeake Bay. There is no fish or other water animal that has
a higher value for edible purposes than the terrapin. The extreme
delicacy of its flavor, the richness of its aroma, and its easy
digestibility give to it a rank which perhaps no other usual food
product possesses. In addition to this the increased scarcity of
the terrapin, especially the more famous variety of it, namely, the
diamond-back, has gradually increased the cost until at the present
time the terrapin is eaten only by the rich. In the United States it
exists along the whole Atlantic coast from New York southward and also
along the Gulf coast. Formerly it was most abundant on the Maryland
coast, but the nearness of this field to the great markets of the
country has resulted in such a depletion of the stock as to make the
terrapin very scarce. Many attempts have been made at artificial
growing of terrapin and these have been more or less successful, but
have not met with pronounced success which has been expected. The
enclosure in which the terrapin are kept, viz., the “crawl,” is a
feature in the artificial cultivation or breeding of these marine
vertebrates. It is to be hoped that greater success in the future will
attend the artificial breeding of terrapin, since the natural stock
seems well on the way to extinction.
_Composition of the Terrapin._--Edible portion:
FRESH. DRY.
Water, 74.47 percent
Protein, 21.23 „ 83.13 percent
Fat, 3.47 „ 13.59 „
Ash, 1.02 „ 3.99 „
=The Mussel.=--The mussel may be described as a fresh-water oyster. It
occurs in almost all parts of the United States in the fresh waters and
in external appearance resembles to some extent the oyster, but the
shell is usually smoother. In the mussel is often developed concretions
of the carbonate of lime in a particular form known as pearls. In fact
the chief value of the mussel is in the supply of pearls which they
furnish, since their flesh, although often eaten, is not considered
very palatable nor desirable. Pearls may be found in mussels in
every locality, but in some regions they are more abundant than in
others,--for instance, the mussels of Wisconsin are especially noted
for the occurrence of the pearls. Pearls are also frequently found in
oysters, but by no means so frequently as in the mussel.
_Composition of the Mussel._--The edible portion of the mussel forms
about one-half its weight.
Water, 78.64 percent
Protein, 12.51 „
Fat, 1.67 „
Ash, 1.73 „
Undetermined, 5.45 „
=Oysters.=--Oysters belong to a class of animals known as mollusks.
They grow in salt or brackish water and are found along almost the
whole of the coast of the United States. They exist in the greatest
abundance along the coast in the vicinity of Long Island Sound,
Norfolk, Virginia, along the coast of the Gulf of Mexico, off the coast
of Mississippi, Louisiana, and Texas, and along the Pacific coast from
San Francisco to the northern limits of Washington.
_Size._--The size of an oyster depends greatly upon its food and also
upon its species. There are some varieties which at a given period of
growth are naturally very much larger than others. The larger variety
grows near Norfolk and along the Gulf coast. A smaller species is
especially abundant on the Pacific coast, though a number of very large
specimens of oysters have been found on that coast.
_Age._--An oyster is eaten at any time after two years. Oysters,
however, three or four years old are, perhaps, in all respects the
best. The age is determined largely by the appearance of the shell,
experts being able to practically determine the age of an oyster by an
examination of the shell.
The oyster grows within a shell which is composed almost exclusively
of carbonate of lime. The periphery of the shell is ovoid in shape,
irregular, and the surface, especially of old oysters, is corrugated,
rough, and unattractive. The interior of the shell is smooth and
generally white, but sometimes has a blue or reddish tinge. The shells
of edible oysters vary in size from 2 to 6 inches in length and from
2 to 4 inches in width. The oysters sold in the market are known by
various names, usually derived from the location from which they come.
A small variety distinguished by a blue color on the inside of the
shell is known as blue points. The real blue points come only from Long
Island. Another variety named Rockaway is also a Long Island variety,
and should come exclusively from Rockaway or vicinity. Shrewsbury is
another highly prized variety from the neighborhood of Shrewsbury, New
Jersey. Buzzards Bay, James River, Norfolk, Lynnhaven, Rappahannock,
Stony Creek, Saddle Rock, etc., are names commonly found in the trade.
Unfortunately, the name of the location is not always an indication of
the actual source from which the oysters may have come. For instance
the term “blue point” is now very commonly given to small oysters not
exceeding 2 or 2¹⁄₂ inches in length with a correspondingly diminished
breadth. On the contrary “saddle rock” is a name given to very large
oysters no matter from what region they may come. It is a common
practice to separate the oysters taken from one location into groups of
similar size and attach to each group a special name which may or may
not be indicative of location.
_Cultivation of Oysters._--The natural beds of oysters are rapidly
exhausted by the free fishing which is in some cases allowed, and
the supply must be kept up by proper cultivation. Oyster farming
has become a great industry along all parts of the coasts where the
conditions are well suited to culture. The ideal conditions are inlets
where the oysters are protected from the action of ocean waves and
where abundant food can be derived from the low marshy grounds in the
vicinity. The laws in force in the states protect the oyster farms
from poachers and deeds are given for oyster beds which are beyond the
low water line. The conditions of culture vary in various states. The
public beds are also protected by law in many states and incipient
war is sometimes carried on between the authorities of one state and
the poachers from other states. Maryland, especially, has laws of a
very strict character respecting the taking of oysters, and the state
furnishes armed forces for the protection of public beds.
_Season for Oysters._--The best season for oysters on the Atlantic
coast of the United States extends from September first to May. These
dates may also be applied to oysters of the Gulf and Pacific coasts.
It is commonly said that all months which have an “R” in them are
suitable for eating oysters. In point of fact oysters are eaten the
year round, especially on the Atlantic coast, though to a very limited
extent during the spring and summer months. Those who own their own
oyster beds are privileged to take oysters at all seasons, and it is
not unusual that a restaurant furnishes oysters during the whole year,
those in the closed season being derived from private beds.
_Life of an Oyster._--After an oyster is taken from its bed it may be
kept alive for a long time at a temperature which does not rise too
high nor sink too low. The best temperature for keeping oysters alive
is about 40 to 50 degrees Fahrenheit. The oysters should be protected
from the sunlight by a proper covering in a cool place and kept moist
with sea water or brine which is sprinkled over them in such a way as
to come in contact with each oyster in the heap. Oysters kept under
these conditions often remain in an excellent state for consumption for
a week or ten days or even longer. If such conditions are maintained
oysters may be shipped in bulk to all parts of the country in cars kept
cool, and this is the best way in which oysters should be distributed
for consumption in a fresh state.
The treating of oysters with fresh water in order to swell them and
thus make them appear larger and plumper than they really are is a
treatment which is reprehensible in every respect. Not only does
it deceive the customer in regard to the size of the oyster but it
deprives the oyster of its proper taste and flavor. “Soaked” oysters
quickly lose their flavor, whereas the oysters kept as above described
and sprinkled with brine retain their natural flavor and odor. The
objection to the transportation of oysters in this way is that the
shell usually weighs many times more than the oyster and the same
rate of freight must be paid upon it as upon the oyster itself.
Nevertheless, the fact remains that fresh oysters should be eaten
directly after removal from the shells. As soon as the shell is removed
and the oyster killed by this removal it begins to deteriorate and in a
short time its flavor and aroma are impaired. It is a common practice
in many cities, even where oysters are delivered fresh daily from
their beds, to open large quantities of them and put them in tubs and
sell them from these tubs to customers. It thus happens that customers
often buy oysters that have been opened 24 hours or more and which are
naturally of a very changed flavor. Strict regulations in regard to the
use of fresh oysters, favoring their being opened when they are ready
for consumption or requiring that they should be kept in the condition
of palatability and properly kept cool until ready for consumption,
should be observed.
_Shipment of Opened Oysters._--Opened oysters are shipped extensively
to all parts of the country. After removal from the shell the oysters
are washed to remove the natural water, since this becomes ropy during
shipment. They are then packed in wooden tubs of various sizes, a
piece of ice added, covered, and delivered to the fast express or
freight service. In this way the oysters may be kept free of dangerous
deterioration for several days. In such cases care must be exercised
to keep the temperature low and to secure a sanitary environment.
Thus protected the oysters should arrive at their destination without
any further change than the necessary loss of flavor caused by the
conditions of preparation and transportation.
_Proportion of Shell and Oysters._--The following illustration (Report
of the U. S. Commissioner of Fish and Fisheries for 1888, page 784)
shows the relative proportion of the flesh, liquid, and refuse for two
or three varieties of oysters:
Name: Oysters (“East Rivers”).
Locality: Cow Bay, Long Island Sound, New York.
Received: April 8, 1881, from E. G. Blackford.
Description: Length, 2¹⁄₂ to 5¹⁄₂ inches; breadth, 1³⁄₄ to 3¹⁄₂
inches.
WEIGHINGS IN PREPARATION FOR ANALYSIS.
GRMS. LBS. OZ. PERCENT.
Flesh, 558.0 1 3.6 10.27
Liquid, 543.7 1 3.1 10.01
Refuse (shells, etc.), 4,284.7 9 7.2 78.86
Loss, 47.3 .. 1.7 .86
------- -- ---- ------
Total, 51 oysters, 5,433.7 11 15.6 100.00
Name: Oysters (“Sounds”).
Locality: Princess Bay, Staten Island, New York.
Received: November 30, 1881, from Dorlon & Shaffer, New York City.
Description: Thirty oysters in shell.
WEIGHINGS IN PREPARATION FOR ANALYSIS.
GRMS. LBS. OZ. PERCENT.
Flesh, 384.0 .. 13.5 8.24
Liquid, 436.0 .. 15.4 9.35
Refuse, 3,816.0 8 6.6 81.87
Loss, 25.0 .. 0.9 0.54
------- -- ---- ------
Total, 30 oysters, 4,661.0 10 4.4 100.00
The above data show that for 100 pounds of shelled oysters only about
10 pounds of meat are found. There is also about 10 pounds of liquid
or juice that escapes when the oyster is opened. There is an average
of 80 pounds of shell and other refuse. When it is remembered that, as
will be shown in the table given below, in 10 pounds of the meat there
is over 80 percent of water it is seen that the actual nourishment
contained in 100 pounds of oysters is reduced to a little over 1 pound.
There is a general opinion that oysters are a very nutritious food and
this is true in so far as the nitrogenous element of food, that is, the
protein, is concerned, and in proportion to the quantity present. As a
nourishing food the oyster cannot be considered as worthy of any very
great esteem. It must be confessed that it will continue to be used as
it has been in the past, that is, practically, as a condimental food
substance and not to satisfy hunger nor provide the heat and energy of
the human activities.
_Process of Floating._--Reference has already been made to the practice
of soaking oysters in fresh water for the purpose of making them
more plump and increasing their weight. This, in the language of the
fisherman, is called “floating,” “drinking,” or “laying out.” By this
process the body of the oyster affects a plumpness and largeness which
materially increases its selling qualities, as it increases its weight
and size and, therefore, the profits of the dealer. The principle of
this process depends upon the fact that when a soft substance like an
oyster, containing a mineral salt in its composition, is brought in
contact with water, a process of diffusion takes place which is known,
in chemical physics, as osmosis, whereby water passes through the cell
walls and enters the cells of the oyster and the mineral substance
thereof is forced out into the external water. Larger volumes of water
pass into the cells than accompany the particles of mineral matter to
the outside of the cells and the result is a swelling of the oysters
and consequent increase in the size and weight by the addition of pure
water, but at the expense of the natural salt, mostly chlorid of sodium
or common salt, which the oyster contains.
The U. S. Bureau of Fisheries has been experimenting to show the change
which takes place with the following results:--
STATISTICS OF WEIGHTS, ETC., OF SPECIMENS OF OYSTERS.
----------------+-------------------------------------+
| JAMES RIVER.[17] |
----------------+------------------+------------------+
| | |
CONSTITUENTS. | From beds. | From floats. |
+------------------+------------------+
| Lab. No. 82; 31 | Lab. No. 83; 34 |
| oysters. | oysters. |
----------------+-------+----------+-------+----------+
Shell contents: |_Grms._|_Lbs. Oz._|_Grms._|_Lbs. Oz._|
Flesh (body) | 312.5| 11.0| 412.5| 14.5|
Liquids (liquor)| 181.5| 6.4| 208.0| 7.3|
+-------+----------+-------+----------+
Total | 494.0| 1 1.4| 620.5| 1 5.8|
+=======+==========+=======+==========+
Refuse: | | | | |
Shells | 2778.0| 6 2.0| 2976.0| 6 9.1|
Loss[18] | 21.0| 0.8| 17.5| 0.6|
+-------+----------+-------+----------+
Total | 2799.0| 6 2.8| 2993.5| 6 9.7|
+=======+==========+=======+==========+
Total weight of | | | | |
specimen | 3293.0| 7 4.2| 3614.0| 7 15.5|
----------------+-------+----------+-------+----------+
----------------+-------------------------------------
| POTOMAC RIVER.[17]
----------------+------------------+------------------
| |
CONSTITUENTS. | From beds. | From floats.
+------------------+------------------
| Lab. No. 85; 35 | Lab. No. 84; 41
| oysters. | oysters.
----------------+-------+----------+--------+---------
Shell contents: |_Grms._|_Lbs. Oz._|_Grms._|_Lbs. Oz._
Flesh (body) | 302.5| 10.7| 415.5| 14.7
Liquids (liquor)| 282.0| 10.0| 264.3| 9.3
+-------+----------+-------+----------
Total | 584.5| 1 4.7| 679.8| 1 8.0
+=======+==========+=======+==========
Refuse: | | | |
Shells | 3017.0| 6 10.4| 3386.0| 7 7.4
Loss[18] | 22.5| 0.8| 15.2| 0.5
+-------+----------+-------+----------
Total | 3039.5| 6 11.2| 3401.2| 7 7.9
+=======+==========+=======+==========
Total weight of | | | |
specimen | 3624.0| 7 15.9| 4081.0| 8 15.9
----------------+-------+----------+-------+----------
[17] Transplanted to beds in New Haven harbor, Connecticut, in April,
and taken for analysis the following November.
[18] Loss in opening and weighing, chiefly water.
COMPARATIVE PERCENTAGE COMPOSITION OF OYSTERS BEFORE AND AFTER
“FLOATING.”
-------------------------+---------------------+---------------------
|JAMES RIVER OYSTERS |POTOMAC RIVER OYSTERS
| TRANSPLANTED TO | TRANSPLANTED TO
| NEW HAVEN. | NEW HAVEN.
-------------------------+----------+----------+----------+----------
CONSTITUENTS OF OYSTERS. | As taken | As taken | As taken | As taken
| from | from | from | from
| beds. | floats. | beds. | floats.
+----------+----------+----------+----------
| No. 82. | No. 83. | No. 85. | No. 84.
-------------------------+----------+----------+----------+----------
_In whole specimen:_ |_Percent._|_Percent._|_Percent._|_Percent._
Shell contents: | | | |
Flesh | 9.49 | 11.41 | 8.35 | 10.18
Liquids | 5.51 | 5.76 | 7.78 | 6.48
+----------+----------+----------+----------
Total shell | | | |
contents | 15.00 | 17.17 | 16.13 | 16.66
+==========+==========+==========+==========
Refuse: | | | |
Shells | 84.36 | 82.35 | 83.25 | 82.97
Loss in preparation | | | |
for analysis | 0.64 | 0.48 | 0.62 | 0.37
+----------+----------+----------+----------
Total refuse | 85.00 | 82.83 | 83.87 | 83.34
+==========+==========+==========+==========
Total constituents,| | | |
shell contents, and| | | |
refuse | 100.00 | 100.00 | 100.00 | 100.00
+==========+==========+==========+==========
_In flesh (body):_ | | | |
Water | 77.99 | 82.77 | 77.90 | 82.06
Water-free substance | 22.01 | 17.23 | 22.10 | 17.94
+----------+----------+----------+----------
Total flesh | 100.00 | 100.00 | 100.00 | 100.00
+==========+==========+==========+==========
In water-free | | | |
substance: | | | |
Nitrogen | 1.70 | 1.40 | 1.65 | 1.45
Protein (nitrogen × | | | |
6.25) | 10.63 | 8.79 | 10.31 | 9.09
Fat (ether extract) | 2.61 | 1.91 | 2.33 | 1.93
Ash | 2.21 | 1.55 | 2.17 | 1.58
Carbohydrates, etc. | | | |
(by difference) | 6.56 | 4.98 | 7.29 | 5.34
+----------+----------+----------+----------
Total water-free | | | |
substance | 22.01 | 17.23 | 22.10 | 17.94
+==========+==========+==========+==========
_In liquids:_ | | | |
Water | 94.74 | 95.22 | 94.99 | 95.69
Water-free substance | 5.26 | 4.78 | 5.01 | 4.31
+----------+----------+----------+----------
Total liquids | 100.00 | 100.00 | 100.00 | 100.00
+==========+==========+==========+==========
In water-free | | | |
substance: | | | |
Nitrogen | 0.31 | 0.34 | 0.29 | 0.33
Protein (nitrogen × | | | |
6.25) | 1.95 | 2.09 | 1.81 | 2.05
Fat (ether extract) | 0.04 | 0.13 | 0.02 | 0.01
Ash | 2.54 | 1.42 | 2.47 | 1.19
Carbohydrates, etc. | | | |
(by difference) | 0.73 | 1.14 | 0.71 | 1.06
+----------+----------+----------+----------
Total water-free | | | |
substance | 5.26 | 4.78 | 5.01 | 4.31
+==========+==========+==========+==========
_In total shell contents,| | | |
flesh, and liquids:_ | | | |
Water | 84.15 | 86.95 | 86.14 | 87.36
Water-free substance | 15.85 | 13.05 | 13.86 | 12.64
+----------+----------+----------+----------
Total shell | | | |
contents | 100.00 | 100.00 | 100.00 | 100.00
+==========+==========+==========+==========
In water-free | | | |
substance: | | | |
Nitrogen | 1.19 | 1.05 | 0.99 | 1.02
Protein (nitrogen × | | | |
6.25) | 7.44 | 6.54 | 6.20 | 6.37
Fat (ether extract) | 1.66 | 1.31 | 1.21 | 1.18
Ash | 2.32 | 1.50 | 2.32 | 1.43
Carbohydrates, etc. | | | |
(by difference) | 4.43 | 3.70 | 4.13 | 3.66
+----------+----------+----------+----------
Total water-free | | | |
substance | 15.85 | 13.05 | 13.86 | 12.64
+==========+==========+==========+==========
_In whole specimen:_ | | | |
Shell contents: | | | |
Water | 12.62 | 14.93 | 13.89 | 14.55
Water-free substance | 2.38 | 2.24 | 2.24 | 2.11
+----------+----------+----------+----------
Total shell | | | |
contents | 15.00 | 17.17 | 16.13 | 16.66
Refuse | 85.00 | 82.83 | 83.87 | 83.34
+----------+----------+----------+----------
Total shell | | | |
contents and refuse| 100.00 | 100.00 | 100.00 | 100.00
+==========+==========+==========+==========
_In whole specimen:_ | | | |
Shell contents: | | | |
Nitrogen | 0.18 | 0.18 | 0.16 | 0.17
Protein (nitrogen × | | | |
6.25) | 1.12 | 1.12 | 1.00 | 1.06
Fat (ether extract) | 0.25 | 0.22 | 0.20 | 0.20
Ash | 0.35 | 0.26 | 0.37 | 0.24
Carbohydrates, etc. | | | |
(by difference) | 0.66 | 0.64 | 0.67 | 0.61
+==========+==========+==========+==========
Total water-free | | | |
substance | 2.38 | 2.24 | 2.24 | 2.11
Water | 12.62 | 14.93 | 13.89 | 14.55
+----------+----------+----------+----------
Total shell-contents | 15.00 | 17.17 | 16.13 | 16.66
+==========+==========+==========+==========
---------------------------------------------------------------------
_Result of Treatment._--As shown by the data the first result is one
which would naturally be expected, namely, that the total weight of
the oyster thus inflated with water is increased relatively to the
total weight of the shell since no change takes place in the weight
of the shell during floating. The gain of weight in the oyster is due
to the absorption of the water, although there is a loss of mineral
salt. The average gain of the oyster was, in round numbers, 10 percent.
The danger of infecting oysters thus treated with any germs, which
may be present in the water or ice used, should also be taken into
consideration.
In respect of the composition of the oyster itself when subjected to
floating the chief change is in the increase of the water content. As
has already been said the process of floating is fatal to the flavor
and palatability of the product.
_Adulteration._--The chief adulterations of oysters are the “floating”
above described and the treatment of the “shucked” oysters with
formaldehyde, boron compounds, and other preservatives to keep them
from spoiling. These processes are thoroughly reprehensible and are
rapidly disappearing. The consumer who lives near the source of
supply should never eat any but freshly shelled oysters and those at
a distance confine themselves to the properly prepared and shipped
article. The chief delight of the epicure is the freshness, and not the
quantity of nourishment of this justly prized bivalve.
_Average Composition of Oysters:_[19]--
Water, 60.08 percent
Solids, 39.92 „
Nitrogen, 1.56 „
Phosphoric acid, .42 „
Sulfur, .19 „
Fat, 9.48 „
Ash, 1.77 „
Protein, 9.73 „
[19] Average of samples used at Hygienic Table, Bureau of Chemistry.
ANIMAL OILS.
The same distinction is made between oils and fats for animal products
as has been made for the vegetable preparations further on. An animal
fat remains solid or semisolid at the ordinary temperature of the
living room. An animal oil, on the other hand, is one which at ordinary
temperature is a liquid. Animal oils, as a rule, are not used for
edible purposes directly, but are used to some extent in cooking, and
to a large extent as medicinal food. Inasmuch as these oils are used
for medicinal food purposes, those which are most important in this
use may be very properly described in this manual. As these oils are
derived both from sea and land animals they are often conveniently
divided into marine animal oils and terrestrial animal oils. There is
also a marked difference as a rule between the oils of marine origin
and those of terrestrial origin. The oils of marine origin, as a rule,
have a very high iodin number while the animal oils of terrestrial
origin have an iodin number not much greater than the fats from which
they are derived. This distinction corresponds somewhat closely to
those vegetable oils which belong to the drying and non-drying variety.
The iodin number represents the percentage of iodin absorbed by a unit
weight of substance. If one gram of an oil absorb 0.67 gram of iodin,
the iodin number is 67. The marine oils correspond to the dry vegetable
oils and the terrestrial oils to the non-drying vegetable oils. While
this difference is one which is marked, it does not always exist in
each individual case.
MARINE ANIMAL OILS.
The marine animal oils may be conveniently divided into fish oils,
liver oils, and blubber oils. Of these the liver oils are the most
important from an edible point of view or a medicinal edible point of
view. The fish oil and blubber oil are used chiefly for illuminating
and other technical purposes.
=Fish Oils.=--These are obtained by rendering from all parts of a fish
where fat exists. The herring, sardine, salmon, and the menhaden are
the fish which are chiefly used for getting oil of this kind. The fish
oils have very much improved in quality since the steamer has taken the
place of the sail boat for gathering the fish. During the days of the
sail boat the fish were often kept for ten days after seining before
they were brought ashore. The decomposition which took place would
naturally affect the oil. At the present day the steamers fishing close
to the shores deliver their products much more frequently, often the
same day they are caught, and thus a better quality of oil is produced.
In this country menhaden is the chief fish used for obtaining oil.
The scientific name of menhaden is _Brevoortia tyrannus_. These fish
appear in enormous quantities around the Atlantic coast from May until
November. It is estimated that nearly one-half million tons have been
taken of these fish during a season. Menhaden oil is rarely if ever
used for edible purposes. It is used principally in the leather trade
and sometimes in the adulteration of cod liver oil made in Newfoundland.
_Sardine Oil._--Sardine oil is principally prepared in Japan from the
Japan sardine (_Clupea sardinus_). It is not used to any extent for
edible purposes. It is also prepared to some extent in the boiling of
sardines in France preparatory to packing in oil.
_Salmon Oil._--This oil is obtained in large quantities on the Pacific
coast. It is one of the fish oils which has an agreeable odor and taste
and, therefore, can be used for edible purposes. It has a specific
gravity at 15 degrees of about .926 and its iodin number is about 160.
_Cod Liver Oil._--The most important of all the animal oils for food
purposes is the oil which is obtained from the liver of the cod (_Gadus
callarias_). Cod liver oil is valuable for food purposes not on account
of its odor and taste, which are usually quite disagreeable, but by
reason of the specific effect which it is often said to exercise in
cases of emaciation and general disorder of the functional activities
of the body. It is a food or medicine, whichever it may be best called,
which is highly prized in tuberculosis and similar diseases. The oil
is chiefly prepared in the Loffoden Islands. Different classes of oil
are prepared which are differentiated chiefly by their color, the
lighter the color the higher the quality of the oil. The chemical
composition of cod liver oil is extremely complex, many different
kinds of substances having been found in it by various authorities.
The probability is that many of these supposed substances are only
mixtures of others. Yet it cannot be denied that the number of chemical
compounds occurring in cod liver oil is very much greater than that
which occurs in ordinary oils. Both the medicinal and food values of
the oil are often attributed to these bodies which occur in minute
quantities.
_Properties._--Cod liver oil at 15 degrees has a specific gravity of
.922. Its iodin number varies very greatly but is always high, ranging
from 150 to 180. Its refractive index is also very high, namely 1.47.
An important constituent of cod liver oil is cholesterol. Cod liver oil
contains naturally a small quantity of iodin and this natural compound
of iodin is one of the properties to which much of its medicinal virtue
has been attributed. The quantity present is extremely minute, and
probably never exceeds .002 of one percent.
_Adulteration of Cod Liver Oil._--Owing to its increasing price cod
liver oil has been subjected to many forms of adulteration. The chief
adulteration consists in the admixture of fish liver oil of lower
quality or the use of blubber oil. Seal and whale oils have been used
very extensively in the adulteration of cod liver oil. Japan fish
oil and, in fact, all other fish oils which are of a character not
to disguise the properties of cod liver oil have been used. It is
evident that it is with extreme difficulty that the presence of these
adulterants can be detected, especially if they are used in small
quantities. The only certain method of guarantee of the purity of a cod
liver oil is in the proper inspection and control of the manufacturing
works. The livers of many other kinds of fish are employed in the
manufacture of cod liver oil, but the other varieties have little
value as compared with the cod liver oil itself and they are probably
used almost exclusively in the adulteration of the genuine article.
The Norwegian cod fish gives a much better character of oil than those
coming from the Atlantic coast of America. In fact the latter product
is of little medicinal food value and is used chiefly in the leather
trade.
=Blubber Oil.=--Blubber oil includes the oils made from seals, whales,
turtles, etc., and is used exclusively for technical purposes, unless
surreptitiously placed in cod liver oil as an adulterant.