2. Oysters, and the class called white-fish, are more easily digested than meat, hence they should be chosen for invalids or those having weak digestions. Kinds of fish: 1. White-fish.--The fat is stored mostly in the liver, making the flesh easy to digest. Examples: cod, halibut, haddock, white-fish. 2. Oily fish.--The fat is distributed throughout the flesh, making it more difficult to digest. Examples: salmon, herring, mackerel. 3. Shell-fish.--Because of their close fibres, these are difficult to digest, with the exception of oysters. Examples: clams, scallops, and oysters. 4. Crustaceous.--The flesh is tough and hard to digest. Examples: lobsters, crabs. Selection of fish: Fresh fish may be recognized by the following: 1. The eyes should be full and bright. 2. The flesh should be firm and elastic. 3. The gills should be bright red. 4. There should be no unpleasant odour. Cooking of fish: Fish may be cooked in any way similar to meat. As the flesh of fish contains food substances which are very easily dissolved in water, boiling is not a good method of cooking to choose for this food. Steaming, baking, and frying are more suitable. GELATINE A lesson on gelatine naturally follows the lessons on meat and fish. The study of bone and the making of soup have explained the source of this substance, and only a few additional facts are necessary. The gelatine practice dishes are sure to prove attractive to the class, and the common use of this food in sickness, and in salads and desserts, makes it important that its food value be understood. 1. Source of gelatine: Gelatine is obtained from the bones, cartilage, and skin of animals. It is the connective tissue dissolved out of these parts. The housekeeper may obtain it for herself or she may buy it already extracted; both are equally good. 2. Commercial forms: (1) Sheet gelatine (2) Shredded gelatine (3) Granulated gelatine. 3. Properties of gelatine: (1) It softens in cold water, but will not dissolve. (2) It dissolves in hot water. (3) It jellies when cold, if the solution be sufficiently strong. (4) Good gelatine has little taste, colour, or odour, and no sediment when dissolved. 4. Steps in dissolving gelatine: (1) Put a small amount of cold water or any cold liquid on gelatine, and let it stand until the liquid is absorbed. (2) Add a boiling liquid and stir thoroughly until dissolved. 5. Value in the diet: (1) Gelatine is a nitrogenous substance, but cannot of itself build tissues, as most protein foods do. When eaten, it will save the tissues already making up the body, hence is called a _protein-sparer_.