Starch is abundantly present in all the more common forms of vegetable diet. Is exists in a state of almost absolute purity in the substances known as arrowroot, tapioca, and sago. These substances from whatever source obtained, contain little or no nutritious or flesh-forming food, and, consequently, ought never to become the substantive diet of human beings. Many plants contain so large quantities of starch, and so small quantities of flesh-forming matter, that they ought only to be taken on account of their starch. Such are the potato and rice, in which the quantity of starch to flesh-forming matter is as 14 to 1, whilst in wheat it is only as 5 to 1. Potatoes and rice, therefore, can never form the staple article of the diet of the people of this country, who need a large quantity of force-producing matter in order to enable them to perform their work. Starch is extensively used in the arts manufactures, and for domestic purposes. It is prepared for this purpose from the potato, wheat, rice, flour, and the coarser kinds of sago. In Cases 6 and 16 is an extensive series of starches, sago, arrowroot, tapioca, &c. &c., from various parts of the world. The following table gives the quantities of Starch in 100 parts of various kinds of food:— Rice 74 Beans 36 Maize 60 Lentils 35 Wheat 59 Parsnips 17 Rye 51 Potatoes 15 Buckwheat 50 Mangel Wurzel 12 Bread 48 Carrots 11 Barley 48 Turnips 10 Oats 39 Cabbage 4 Peas 37 SEA-WEEDS USED AS FOOD. Sea-weeds contain lichen starch, and are frequently used as food. Specimens may be seen in Case 7. In China the people are very fond of sea-weeds, and many kinds are collected and added to soups, or eaten alone with sauce. In times of scarcity the poorer inhabitants of the sea-shores of Europe have recourse to sea-weeds for a supply of food. THE POTATO. Although this plant contains but a small quantity of flesh and force-producing matter, it yields an abundance of starch and mineral matters in a condition which acts very beneficially on the human system, and its introduction into Europe has been of the greatest benefit to its teeming populations.