HIPPOPOTAMUS. ivory of the great canine teeth, which sometimes excued 30 inclies in length; but this ivory is not as much valued now as it was early in the nine- teenth century, when it was in demand for the making of artificial teeth. The Pygmv or Liberian Hippopotamus. Con- cerning this small species not much is known. It appears to be restricted to the Guinea coast, and to be much less aquatic than its large rela- tive. It wanders and seeks its food in swampy woods, after the manner of a pig, but never gathers in herds. It is about 5Vi: feet long, 2Vl! feet tall, and weighs about 400 pounds. In color it is bluish black along the back, paling gradually to greenish white on the ventral parts. The fact that it has only one pair of incisor teeth, instead of two, in the lower jaw, led Leidy to classify it in a separate genus (Cha'ropsis) . Fossils. Remains of the hippopotamus have been found in the Pliocene and Pleistocene depos- its of India, Burma, Algeria, and Europe. Hippo- potami roamed in herds over England not very long before the period of the earliest human occu- pation, and the remains of individuals of all sizes have been found in the gravels near Cambridge. Remains of dwarf species, associated with those of dwarf elephants, are found in the cave and fissure deposits of the islands of Sicily and Malta. No rerhains of fossil hippopotami have yet been foimd in America. Bibliography. Consult general works, espe- ciallj' Wright, Standard Natural History, vol. v. (Boston, 1885) ; Oakley and Boyd-Dawkins in Casscll's Natural Histori/. vol. ii. (New York, 1884). Consult also the writings of African ex- plorers and sportsmen, especially the earlier ones, as Livingstone, Gordon-Cumming, and Speke ; also Schweinfurth, Heart of Africa (London, 187.3) ; Holub, Seven Years in South Africa (London, 1881); Baker, Wild Beasts and Their Ways (London, 1890). See Plate of Tapirs and Hippopotamus; and Colored Plate of Pachyderms. HIP'PO EE'GITJS. See Hippo. HIPPOTH'OON (Lat., from Gk. ■IttttoWo.;'). The hero of the Attic tribe Hippothoontis. He was the son of Poseidon and Alope, the daughter of Cereyon of Eleusis, and was exposed as a new- born infant, but was suckled by a mare and brought up by shepherds. When Theseus over- came and killed Cereyon, he transferred the gov- ernment to Hippothoon. HIPPU'RIC ACID (from Gk. ?jnrof, hippos, horse + ovpnv, ouron, urine), CjIIoNOj. A com- pound of great interest, both to the chemist and to the physiologist. It derives its name from its hiiving been first discovered in the urine of the horse, and that fluid, or the renal secretion of the cow, affords us the best and readiest means of obtaining it. The fresh urine is boiled with a slight excess of milk of lime anil filtered; the filtrate is evaporat<>d to a small volume, cooled, and acidified with hydrochloric acid, when hip- puric acid separates out in the form of fino needle-like crystals. When obtained by a proc- ess of slow crystallization, the crystjils of hippu- ric acid are moderately large, at first colorless, but subsequently becoming milk-white, four- sided prisms, which are devoid of odor, but have a faintly bitter taste. They dissolve readily in boiling water and in spirit, but are only sparing- ly soluble in cold water and in ether. Its chemi- 97 HIRADO. cal name is benzoyl-amido-acetic acid, CeHjCO. NH.CII2COOH, and it may be prepared artificial- ly from benzoic acid, C'sHiCUUH, and glycin, NHjCHaCOOH. When boiled with strong min- eral acids, hippuric acid takes up water and splits up again into its chemical components, ben- zoic acid and glycin. It is a normal constitu- ent of the urine of the horse, cow, sheep, goat, hare, elephant, etc., and most probably is to be found in the urine of all vegetable feeders. In normal human urine, if the food is an ordinarj' mixed diet it occurs in verj' small quantily, but is increased by an exclusively vegetable diet, and in the well-known disease diabetes: Although hippuric acid usually occurs in mere traces in human urine, we can artificially produce it at will in the body, and cause it to be eliminated in comparatively large quantity. If we suallow benzoic acid, it seems to take up the elements of glycin in its passage through the system, and thus to form hippuric acid, which appears abun- dantly in the urine. Hippuric acid is formed in the animal body not only from benzoic acid itself, but from any substance (e.g. kinic acid) that may be readily transformed into benzoic acid. Some such substances are contained in grass, hay, and in many berries, and are also found among the products of the putrefaction of pro- teids, especially those of vegetable origin. In carnivora the formation of hippuric acid has been shown to take place chiefly in the kidneys; in the herbivora, however, benzoic acid is largely transformed into hippuric acid even if the kid- neys have been removed. In birds the ingestion of benzoic acid causes the formation not of hip- puric, but of cenanthylic acid. The hippuric acid which occurs in the animal organism exists in combination with bases, chiefly as hippurate of soda and hippurate of lime. The last-named salt can be obtained by the mere evaporation of the urine of the horse. HIPPTIRITES, hip'puri'tez (Neo-Lat. nom. pi., from Gk. iwirovpis, hippouris. horse-tailed, from (TTTro!, hippos, horse + ovpi, oura, tail). A remarkable fossil pelecypod in which one valve is a greatly elongated cone and the other a flattened lid. The lower conical valve was attached to the sea bottom by its apex. The upper lid-like valve is provided on its lower surface with elongated processes that project downward into pits in the cavity of the lower valve, and act as levers to raise the lid. Hip- purites shells are exceedingly abinidant in the shallow-water deposits of the Middle and Upper Cretaceous in the Mediterranean region of Eu- rope. See RrniST-^E. HIPUEINA, e-po5're-na'. A cannibal tribe of the middle Purus of Western Brazil, one of the most warlike on the river, and estimated at perhaps 2.500 souls. They live in long, low houses built of converging poles, and use poisoned arrows with heads notched so as to break ofT in the wound. They wear only the breech-cloth, but are clean and self-respecting. HIRADO, he-rli'do (in old books FlKANDO). An island in the northwest of the entrance to the Bay of Omura, oflf the coa.t of Hizen, Japan, with a capital of the same name containing 10.- GOO inhabitants. It was made famous in the six- teenth century as the place of welcome to the Portuguese (the first foreigners to visit .Japan), and later, in 1600. to the Dutch, and in 1609 to
