N UDAR, the Calotropis Gigantea of Brown, and the Calotropis mudarii (Bush.), Asclepias gigantea of Linnaeus. Mudar is a plant common in sandy places in many parts of India ; it has a milky juice in its stem, which, as well as the bark of the root, enjoyed such reputation among the native practioners as a medicinal agent as to lead to its use among European practitioners in the East. It was found to be very efficacious in the cure of_ many obstinate cutaneous diseases, such as lepra Arabum and elephantiasis : in syphilitic complaints also and anasarca, it proved so valuable an alterative that it received the name of vegetable mercury. Some use the powder of the bark of the root, but Sir Whitelaw Anslie prefers the dried milky juice, which in a recent state, if taken in large quantity; is poisonous. It was thought to possess some specific quality, but Dr. Duncan, by whom extensive trials were made of it in Britain, showed that this is not correct, but that it is infinitely more valuable from its common medicinal properties, which correspond in every respect, according to him, both in kind and degree, with those of ipecacuan. He even thought that, from the facility with which any quantity could be procured from the province of Bahar, the use of the Brazilian ipecacuan might be altogether dis pensed with in our East Indian settlements.
Besides its practical value as a medicinal agent, the bark of the root possesses the singular property in one of its constituents, Mudarine, of being very soluble in cold water, gelatinising when the solution is heated to 85° or 90° Fehr., and recovering its fluidity on cooling. It is almost the only instance known of any organic body being an ex ception to the general law of the power of solvents being increased by an increase of temperature, as most albuminous substances are solidified by heat. For this reason we here describe the mode of obtaining it, and give a brief sketch of its habitudes. Mudarine is obtained in a state of considerable purity from the tincture of mudar, by macerating the powder of the root in cold rectified spirit. The greater part of the spirit may be recovered by distillation, but the remaining solution, which acquires a much deeper colour though it remains perfectly transparent, is allowed to cool. As the temperature falls, a white granular resin is deposited by a species of crystallisation from a trans parent coloured solution. The whole is allowed to dry spontaneously,
in order that all the resin may concrete. The dry residuum is then treated with water, which dissolves the coloured portion, and leaves the resin untouched. It is to this principle, dissolved by cold water from the resinous extract, that the name Mudarine is given. It has no smell, and is intensely bitter, with a very peculiar nauseating taste. It is exceedingly soluble in cold water at the ordinary tempemturepf the atmosphere, but insoluble in boiling water. It is soluble in alcohol, but the power of this solvent is increased by increase of ,tempe rature. It is insoluble in sulphuric ether, oil of turpentine, and olive oiL It is in the solution in water when nearly saturated that the peculiar property of Mudarine is most easily exhibited. At ordinary tem peratures this solution is quite fluid and transparent. When heat is gradually applied, already at 74° Fahr., a change in its constitution begins to be observable, indicated by a slight diminution of its trans parency. As the temperature is raised these changes increase, and at 90' it has in a great degree lost its transparency, and has acquired the consistence of a tremulous jelly. At 95° it is fully gelatinised, and a separation of it taken place into two parts, a soft brownish coagulum, and a liquid nearly colourless. At 98° the coagulum is evidently contracted in size. At 130° the coagulum seems to dissolve : at 185° the coagulum is very small, and has a tenacious, pitchy con sistence. At 212° little further change occurs. The alterations which in this state it undergoes on cooling deserve to be noticed. At 140° the fluid is very turbid : the coagulum has not diminished in size, and is now very hard and brittle. At 110° fluid less turbid, coagulum remarkably brittle, with a resinous fracture : at 100' fluid more trans parent. When (cooled down even to the freezing temperature the coagulum remains unaltered, and very much resembles colophony; but after the lapse of several days it gradually liquefies in a portion of fluid in contact with it, without passing through the intermediate state of a jelly.
Nateria Indica, vol. i. p. 486 ; Duncan in Min. Dtcd. and Burg. Journ., July, 1329 ; and in Trans. of Royal Society of Edinb., vol. xi. p. 433.)