_Symptoms._ _Ruminants_ without any appreciable cause, lick the clothes of their care-takers, chew and swallow articles of clothing of all kinds, bones, old shoes, gloves, socks, cuffs, collars, small forks, pocket-knives, nails, wires, needles, coins, stones, lumps of clay, hair, which may give rise to secondary troubles of a more or less serious kind. Pregnant cows are especially subject to this infirmity. The small pointed objects like pins, needles, ends of wires, etc., which are mostly taken by accident with the food are especially apt to be entangled in the alveoli of the reticulum and make their way to the heart, with fatal effect, or through the abdominal walls creating a fistula. Hair aggregates with saliva, mucus and phosphates, to form balls in the first two or three stomachs. Other indigestible objects may also become encrusted and prove sources of irritation. Licking the skin of another animal is doubtless at times encouraged by the taste of the salts of perspiration, but in other cases it has all the appearance of a mutual kind service as the cow with itching head will walk up and present it to its fellow which rarely fails to respond to the invitation. Stump licking is not uncommon. =Sheep= shut up in the winter get in the habit of chewing each other’s wool, thus virtually depilating their fellows and accumulating wool balls in their stomachs. =Pigs= when running at large eat human fæces often infecting themselves with the cysticercus cellulosa, and devour their own or their fellows’ bristles, which form ovoid and irritating aggregations in the stomach. =Puppies= are proverbial for swallowing every small object that comes in their way, coal, pebbles, marbles, leather, hair, etc., with the result of inducing nausea and vomiting, or more seriously, wounds of the stomach, gastritis and enteritis. In older dogs the habit is more likely to imply rabies. =Solipeds= will lick and swallow each others hair, eat off the hair from each other’s tails and manes, eat their clothing, lick the wall plaster, earth or sand, and even the manger or rack. The last named habits are usually connected with disease. =Fowls= can digest almost anything they swallow, but if they take to picking their feathers, they create serious injury to the skin and indirectly to the general health. _Causes and Nature._ In general terms it may be said that the causes of depraved appetite are very numerous, so that the trouble must be looked upon as a symptom of many morbid conditions in place of a disease _sui generis_.