In Case 4 are examples of some of the principal Mineral Substances, excepting water, in food. They are generally essential to proper nutrition. In the body of a man, weighing 154 lbs., there are about 8 lbs. of mineral matter. Different parts of the body show peculiar affection for particular ingredients to the exclusion of others. The mineral salts contained in plants and animals are indestructible by heat, hence they are called “ashes.” It should be recollected, that in the boiling of food many of the mineral substances are dissolved out of it, and where the liquid that they are boiled in is not consumed such mineral matters are thrown away. This is the case with boiled meat and vegetables, and a constant use of such food may lead to injurious effects. The best corrective to such a diet is the use of uncooked fruit and vegetables. In this way the eating of ripe fruits, as apples, pears, gooseberries, &c., and salads, has a beneficial effect on the system. SALADS. Although many things eaten as salads contain other constituents of food besides mineral matters their beneficial action in diet is due to the latter. The practice of eating salads is not so common in Europe as before the introduction of the potato, which, to a certain extent, supplies the same kind of mineral matters to the blood. The practice of eating salads is, nevertheless, to be highly commended; and many plants formerly much used might now be consumed in this way with much advantage. Plants thus used contain a larger quantity of mineral matter than vegetables which have been boiled in water. Various plants used as salads may be seen on the shelves, and are renewed from time to time. FORCE-PRODUCERS IN FOOD. In Case 4 may be seen the varieties of substances called “force-producers in food.” STARCH. The substance called Starch is found very abundantly in the vegetable kingdom. Its presence was at one time regarded as characteristic of plants, but it has recently been found in animals. It occurs in the form of irregularly-shaped granules, which vary in size from the 1/400 to the 1/2000-th of an inch in diameter. These granules are simple or compound. They vary in shape and size in every species of plant, and are insoluble in water, but are easily diffused through it. On being mixed with water, and exposed to a temperature of 180°, the starch gelatinises, and, mixing with the water, thickens it. This occurs in the cooking of starch, and this property lies at the foundation of pudding making.