is fit for immediate use; or, if made into cakes, may be preserved for any length of time.
Ivory-black, as imported from Holland, is prepared in the following manner: Small pieces of ivory are smeared with a little lintseed-oil, and put into a black-lead crucible; this is covered with a similar vessel inverted, but of a smaller size, and the crevices are secured with a lute made of potter's clay and rye-flour, so as to prevent the access of external air. Thus prepared, the whole is exposed to a red heat, not too intense, for about half an hour, after which it is taken out and suffered to cool gradually. When cold, the charred ivory, or bones, where the former is scarce, ought to be reduced to powder, and triturated, with the addition of water, on a painter's stone, till it assumes the form of a smooth paste. In this state it is moulded into small cones, and allowed to dry.—Similar black may also be obtained by burning the stones of peaches, after having previously dried them and removed the kernels. This useful fact we state on the authority of Hochheimer, a German writer on general economy.
BLADDER, in anatomy, a thin membranous, expanded receptacle of some juice or humour secreted in the animal body. This term principally applies to the vessels in which the urine and bile are respectively collected; and hence the two chief reservoirs of this nature are the urinary bladder, and that containing the bile. In this place we shall treat only of the former, which is situated within the cavity of the pelvis: its form is oval, and being a continuation of the abdomen, it is almost uniformly surrounded with bones, though below, and at each side, encompassed by muscles. It is remarkable, that this vessel is considerably larger in the female, than in the male sex.
Nature has wisely contrived that the human bladder should possess a high degree of expansion, for containing the watery parts secreted from the chyle, as they would otherwise mix with the blood of animals, and render that fluid too thin for the performance of its functions. Though a large proportion of such aqueous humours, from three to four pounds every day, are insensibly evacuated by the skin, yet a still greater quantity must be secreted by the kidneys, and thence conducted to the bladder, lest they should accumulate between the interstices of the cellular membrane, which covers all the muscles, and occasion dropsical swellings. On the other hand, the diseases incident to the bladder are various, but principally arise from debility, spasms, and calculous concretions; for an account of which, we refer to the articles Gravel, Stone, and Urine. At present, we shall confine ourselves to the inflammatory state of that vessel, which requires immediate relief. This dangerous malady is occasioned by stimulating medicines; gravel or stones lodged in the orifice of the bladder; violent exercise after a long retention of urine, and especially in hot weather; lying in soft, effeminating feather-beds, &c. The symptoms are manifest from an acute burning pain, and tension of the part; frequent inclination to go to stool, and a constant desire to make water, while the patient is in a state of fever. As, under such circumstances, no time should be lest in applying for proper advice,
