Gelatin enters into the composition of all, or nearly all, the tissues of the body. The walls of the microscopic cells of flesh are composed of it. It is found also in cartilage, tendons, connective tissue, bone, and in the larynx and joints. Spiders' webs and the thread of silkworms are gelatin in a liquid state, which solidifies upon exposure to the air. Another kind of gelatin forms the framework of insects, such as the locusts on which John the Baptist fed. It also forms the true skeleton of lobsters, crabs, and shrimps. The edible birds' nests of the Chinese are a delicate kind of gelatin more digestible than some other kinds, for it is made from the saliva of a swallow, and probably contains pepsin. (M. Williams.) The part which gelatin plays as a food is not well understood. Many experiments have recently been made by scientists on dogs and other animals, to test the value of gelatin in this respect. From these experiments the following conclusions have been drawn: 1. That gelatin alone is not sufficient as a food. 2. That although insufficient it is not worthless. 3. That gelatin is sufficient to sustain life when combined with other substances which would themselves be wholly insufficient if given alone. 4. That gelatin must always be flavored to render it digestible and nutritious. Mattieu Williams says: "It would seem that gelatin alone, although containing the elements required for nutrition, needs something more to render it digestible. We shall probably not be far from the truth if we picture it to the mind as something too smooth, too neutral, too inert, to set the digestive organs at work, and that therefore it requires the addition of a decidedly sapid something that shall make these organs act." Gelatin dissolves easily in warm liquid. Albumen coagulates under similar circumstances. The gelatine of commerce is made from the tissues of animals, particularly from the thick skin of certain portions of the body and from the head and feet. When well flavored and in a liquid state as in broths, or of a tender consistency as in well-made jelly, it is a most desirable food for the sick. Lemon and orange juice, strawberry, raspberry, grape, and indeed any fruit syrup, coffee, cocoa, vanilla, wine, brandy, and Jamaica rum, and strong meat broths which have been cleared, may be used for flavoring. The jelly should not be made hard and tenacious, but tender and jelly-like, though firm.