Boiled or steamed Potatoes should turn out floury, or mealy, by reason of the starch granules swelling up and filling the cellular tissue, whilst absorbing the albuminous contents of its cells. Then the albumen coagulates, and forms irregular fibres between the starch grains. The most active part of the tuber lies just beneath the skin, as may be shown by pouring some tincture of guaiacum over the cut surface of a Potato, when a ring of blue forms close to the skin, and is darkest there while extending over the whole cut surface. Abroad there is a belief the Potato thrives best if planted on Maundy Thursday. Rustic names for it are: Taiders, Taities, Leather Coats, Leather Jackets, Lapstones, Pinks, No Eyes, Flukes, Blue Eyes, Red Eyes, and Murphies; in Lancashire Potatoes are called Spruds, and small Potatoes, Sprots. The peel or rind of the tuber contains a poisonous substance called "solanin," which is dissipated and rendered inert when the whole Potato is boiled, or steamed. Stupes of hot Potato water are very serviceable in some forms of rheumatism. To make the [445] decoction for this purpose, boil one pound of Potatoes (not peeled, and divided into quarters.) in two pints of water slowly down to one pint; then foment the swollen and painful parts with this as hot as it can be borne. Similarly some of the fresh stalks of the plant, and its unripe berries, as well as the unpeeled tubers cut up as described, if infused for some hours in cold water, will make a liquor in which the folded linen of a compress may be loosely rung out, and applied most serviceably under waterproof tissue, or a double layer of dry flannel. The carriage of a small raw Potato in the trousers' pocket has been often found preventive of rheumatism in a person predisposed thereto, probably by reason of the sulphur, and the narcotic principles contained in the peel. Ladies in former times had their dresses supplied with special bags, or pockets, in which to carry one or more small raw Potatoes about their person for avoiding rheumatism. If peeled and pounded in a mortar, uncooked Potatoes applied cold make a very soothing cataplasm to parts that have been scalded, or burnt. In Derbyshire a hot boiled Potato is used against corns; and for frost-bites the mealy flour of baked potatoes, when mixed with sweet oil and applied, is very healing. The skin of the tuber contains corky wood which swells in boiling with the jackets on, and which thus serves to keep in all the juices so that the digestibility of the Potato is increased; at the same time water is prevented from entering and spoiling the flavour of the vegetable. The proportion of muscle-forming food (nitrogen) in the Potato is very small, and it takes ten and a half pounds of the tubers to equal one pound of butcher's meat in nutritive value.