Floating of Shellfish.-Oysters and other shellfish, either in the shell, or, more commonly, after shucking, are often subjected to "floating" or "drinking" in fresh or brackish water or else shipped in direct contact with lumps of ice. Both practices cause the shellfish to greatly increase in size, owing to the absorption of an undue amount of water, and if not labelled "floated" the product is adulterated under the federal law and the laws of certain states.

It is, however, not regarded as improper to drink oysters in water of a saline content equal to that in which they will grow to maturity or to wash the shucked oysters in unpolluted, cold or iced water for the minimum time required for cleaning and chilling. After washing they should be drained and packed for shipment in tight receptacles surrounded by ice but protected from the absorption of the water resulting from the melting of the ice.

Nelson advocates the floating of oysters in clean water with a lower salt content than that of the beds because (1) dirt is eliminated, (2) the volume of flesh is increased, (3) a better color and texture are secured, (4) shrinkage is decreased, and (5) the water content during transportation and storage is retained.

Often shellfish is polluted by growing or floating in impure water, handling under insanitary conditions, or packing in unclean receptacles.

As oysters cannot reach the consumer in satisfactory condition it shipped in their own liquor, the loss of food constituents on draining comes up for consideration. Baylac* reports in a liter of the liquor about 2 grams of albumin as well as determinable amounts of urea, ammonium salts, and inorganic matter. The amount of organic matter in the liquor from Mediterranean oysters is greater than in that of oysters from the

ocean.

Scallops.-According to the Maine Experiment Station,† scallops properly handled should contain not less than 20% of dry matter. The following is a summary of analyses of soaked and unsoaked scallops by Sullivan, the swelling of the meats being sufficient in some cases to make 4 gallons fill a 7-gallon keg:

* Comp. rend. soc. biol., 62, 1907, p. 250.

† Offic. Insp., 55, 1913, p. 149.

Amer. Food Jour., 10, 1915, p. 472.

Clams. At the Maine Station it was found that the drained meats of clams, which contained when opened 24.9% of solid matter, took up on soaking over night in salt water sufficient liquid to reduce the percentage of dry matter to 15.3. While it is recognized that clams will not keep in their own liquor, it is insisted that they be rinsed not longer than 1 minute in cold water or else 2 minutes in hot water, followed by 2 minutes in cold water.

Preservatives in Fish and Oysters.-Boric acid and borax in mixture and sodium benzoate form the most common preservatives of salt dried fish and of oysters. In the case of salt codfish, the preservative is sprinkled on the surface.* Such surface application is allowed under the laws of some states, as for example, Massachusetts, and under the federal law, provided directions for the removal of the preservative are given on the package. In opened oysters sold in casks and kegs, boric mixture has been used commonly in solution in the oyster liquor, but is now infrequent. Ishida † calls attention to the presence of a trace of formaldehyde in fresh crab meat and distinct amounts after being preserved 8 months.

Artificial Colors of the coal-tar group are used to give smoked fish a rich brown color. The New York City Board of Health has brought to notice the coloring of cheaper fish in imitation of salmon.

Methods of Analysis.-These are similar to the methods given for

meat.

CONCENTRATED FOODS.

Under the name of "condensed " or concentrated foods or emergency rations" a number of canned preparations are sold for the use of campers, travelers, armies in the field, etc. These consist usually of mixtures of dried ground meats and vegetables, pressed together in compact form, and preserved in tin cans. The claims made for the food value of these preparations are, as a rule, extravagant and erroneous, as shown *Bitting, U. S. Dept. of Agric., Bur. of Chem., Bul. 133, 1911.

† Jour. Pharm. Soc. Japan, 422, 1917, p. 300.

by Woods and Merrill,* who give the following analyses of some of these foods:

CHAPTER IX.

EGGS.

Nature and Structure.-Though eggs of various birds are used to some extent as food, it is the egg of the hen that is in universal use for this purpose, and therefore the one which is here for the most part discussed, bearing in mind that the structure and composition of all varieties of birds' eggs are closely analogous.

Fig. 60 shows the longitudinal section of a hen's egg.

FIG. 60.-Longitudinal Section of a Hen's Egg. a, Shell; b, Double Membrane of Shell; c, Air-chamber; d, Outer, or Fluid Albuminous Layer; e, Thick, Middle Albuminous Layer; f, Inner Albuminous Layer; g, Membrane of the Chalaza; hh, the Chalaza; i, Vitelline Membrane; j, Germ; k, Yolk; 1, Latebra. (After Macé.)

Weight of Eggs.-The average weights of whole and parts of hens' eggs, as given by Langworthy and Serono and Palazzi † (the latter for 1000 eggs), are as follows:

The data given in the following table were obtained by Woods and Merrill:*

AVERAGE WEIGHTS OF EGGS AND PARTS AS PREPARED FOR ANALYSIS.

Proximate Composition. In the following table appear analyses by Woods and Merrill of the samples described above, also the average of analyses of hens' eggs taken from Atwater and Bryant's Compilation: