_Ergotism_ is due to the growth on cereals (and most commonly on the rye) of a poisonous fungus, the _claviceps purpurea_, which produces a deep purple deposit on the grain. If bread made from such flour is eaten for prolonged periods, severe symptoms result; in some cases, a dry rotting of the limbs. There have been several epidemics on the continent, due chiefly to eating bad rye bread. =Starvation Diseases.=—_Simple Starvation_ causes death in a period varying with the previous state of nutrition. Usually death occurs when the body has lost two-fifths of its weight, whether this be after days, months, or years (Chossat). A supply of water prolongs the duration of life, to as much as three times what it would otherwise be. Good nourishment doubles the power of resisting disease; while deficient food prepares the way for many diseases. A large share of the decline in the English death-rate during the last forty years is due to free trade, and the great cheapening of wholesome food which has resulted from it. An ill-balanced is more frequent than a deficient diet. Deficiency of fat is more serious than deficiency of carbohydrates, and deficiency of proteid is most serious. =Scurvy= is caused by the absence of fresh vegetables. The use of the potato and the orange, as well as of lime juice (the juice of citrus limetta), has led to its extinction among adults in this country. In former times, it caused more deaths among seamen than all other causes put together, including the accidents of war. In infants fed upon tinned foods, whether condensed milk or patent foods, a form of scurvy still occurs. Infants fed on new-milk never suffer in this way. If, therefore, it is necessary to feed an infant on condensed milk for many consecutive months, potato gruel or raw meat juice or fresh milk must occasionally be given. _Rickets_ is chiefly due to improper feeding in childhood. The substitution of artificial foods (most of them containing starch) for the natural milk is its chief cause. The lower incisor teeth of an infant appear between the sixth and seventh months. Starchy food given before this age is undigested. Such food likewise leads to less fat and proteid being given, which are essential for growth. Deficiency of lime salts in the food does not cause it, and giving them in food or medicine will not cure it. Enrichment of the diet by cream or failing this by cod liver oil is the best means of preventing and curing it. Abundant fresh air and warm clothing are also necessary. _Relapsing fever_ generally follows epidemics of typhus fever, and is greatly favoured by starvation. Ophthalmia has been chiefly prevalent in charity schools in which the children are underfed, though its essential cause is contagion.