598 H Y P H Y K HYPOCHONDEIASIS (synonyms the spleen, the vapours). As the name implies (from TO v-n-o^ov^pLov, TO, vTToxovSpLa, the soft part of the body immediately under the xoVSpos or cartilage of the breast-bone), hypochondriasis and its symptoms were referred by the ancients, and indeed by physicians down to the time of Cullen, to diseases or derangements of one or more of the abdominal viscera. Cullen classified it amongst nervous diseases, and Falret more fully described it as a morbid condition of the nervous system characterized by depression of feeling and false beliefs as to an impaired state of the health. The subjects of hypochondriasis are for the most part members of fami lies in which hereditary predisposition to degradation of the nervous system is strong, or those who have suffered from morbid influences affecting this system during the earlier years of life. It may be dependent on depressing disease affecting the general system, but under such cir cumstances it is generally so complicated with the symp toms of hysteria as to render differentiation difficult (see HYSTERIA). Hypochondriasis is often handed down from one generation to another in its individual form, but it is also not unfrequently to be met with in an individual as the sole manifestation in him of a family tendency to insanity. In its most common form it is manifested by simple false belief as to the state of the health, the intel lect being otherwise unaffected. We may instance the " vapourish " woman or the " splenetic " as terms society has applied to its milder manifestations. Such persons are constantly asserting a weak state of health although no palpable cause can be discovered. In its more definite phases pain or uneasy sensations are referred by the patient to some particular region, generally the abdomen, the heart, or the head. That these are subjective is apparent from the fact that the general health is good: all the functions of the various systems are duly performed; the patient eats and sleeps well ; and, when any circumstance temporarily overrides the false belief, he is happy and comfortable. No appeal to the reason is of any avail, and the hypochondriac idea so dominates his existence as to render him unable to perform the ordinary duties of life. In its most aggravated form hypochondriasis amounts to actual insanity, delusions arising as to the existence of living creatures in the in testines or brain, or to the effect that the body is materially changed, e.g., into glass, wood, &c. (see INSANITY). The symptoms of this condition may be remittent; they may even disappear for years, and only return on the advent of some exciting cause. Suicide is occasionally committed in order to escape from the constant misery. As there is nothing to treat, medication is of no avail, and recovery can only be looked for by placing the patient under such morally hygienic conditions as may help to take his mind off himself. More generally he lives through the attack rather than is cured of it. See Cullen, Clinical Lectures, pp. 39-57 (London, 1777); Georget, De la Phys. du Syst. Ncrv. (Paris, 1819) ; Eeynolds, System of Medicine, vol. ii. p. 293 (London, 1868); Griesinger, Mental Patho logy and Therapeutics (1867) ; Niemeyer, Practical Medicine (1871). HYPOTHEC (Hypotheca), in Ptoman law, is the most advanced form of the contract of pledge. A specific thing may be given absolutely to a creditor on the understanding that it is to be given back when the creditor s debt is paid ; or the property in the thing may be assigned to the creditor while the debtor is allowed to remain in possession, the creditor as owner being able to take possession if his debt is not discharged. Here we have the kind of security known as pledge and mortgage respectively. In the hypotkeca, the property does not pass to the creditor, nor does he get possession, but he acquires a preferential right to have his debt paid out of the hypothecated property ; that is, he can sell it and pay himself out of the proceeds, or in default of a purchaser he can become the owner himself. The name and the principle have passed into the law of Scotland, which distinguishes between conventional hypothecs, as bottomry and respondentia, and tacit hypo thecs established by law. Of the latter the most im portant is the landlord s hypothec for rent (corresponding to distress in the law of England), which extends over the produce of the land and the cattle and sheep fed on it, and over stock and horses used in husbandry. The law of agricultural hypothec has long caused much discontent in Scotland ; its operation was restricted by 30 & 31 Viet. c. 42, and finally by 43 Viet. c. 12 it has been enacted that the "landlord s right of hypothec for the rent of land, including the rent of any buildings thereon, exceeding two acres in extent, let for agriculture or pasture, shall cease and determine." As a set off the landlord is to have the same rights and remedies against a tenant when six months rent or twelve months rent is due and unpaid as he had formerly against a tenant when twelve months rent or two years rent respectively was due and unpaid. HYRAX, a genus of diminutive plantigrade mammals, the position of which in the mammalian series lias, owing to their apparent affinity with several widely different groups, given rise to considerable controversy. Approach ing the hare in their external appearance and habits, the rhinoceros in their molar teeth and much of their skeleton, the hippopotamus in the form of their lower incisors, and the sloth in the great number of their dorsal vertebrae, they were at first classed with the rodents, and afterwards, by Cuvier, with the pachyderms, where they remained until, on the breaking up of that most heterogeneous of groups, Cape Hyrax. Professor Huxley established the order Ilyracoidea for their reception. They are small, rabbit-like creatures, the largest not exceeding 18 inches in length, covered with a thick soft fur with numerous bristles interspersed. Their ears and legs are short; the tail is represented only by a small tubercle ; and their toes, of which they have four on each foot in front and three behind, are, with the excep tion of the inner one on each hind foot, provided with fiat hoof-like nails. They have twenty-one pairs of ribs a larger number than is possessed by any other mammals except the sloths, which have twenty-three pairs. They are gregarious animals, dwelling in colonies in the crevices of rocks and in the caverns which abound in the hilly regions they frequent, and feeding on grass and other herbage, on roots, fruits, and the tender shoots of plants. There are, according to Dr Gray, thirteen species of Hyrax, many of which are, however, regarded by other authorities as merely varieties. They are all confined to the African continent with the exception of the Syrian hyrax or daman (Ilyrax
syriacus), whose range extends from Abyssinia into Arabia,
