Page:Willich, A. F. M. - The Domestic Encyclopædia (Vol. 1, 1802).djvu/338

306&#93; 306] BON stances. The late Mr. Gone n, a respectable surgeon of London, re- lates the case of a woman naturally five feet six inches high, who was gradually reduced to three feet four inches. In rickety children, the bones are obviously softer than they ought to be in a sound state, owing, perhaps, to their erosion, occasioned by the discharge of an acrimonious humour. In a similar manner, the scurvy has often been remarked to affect these solid parts of the human frame. Hence, in the former instances, attention to a proper diet, gentle friction with coarse cloths, exercise, fresh air, and cold bathing, will frequently change the constitution of such children, insomuch, that at the age of twenty there will not remain the least symptom of their former de- bility. It is generally believed, that the bones, in a healthy state, are in- sensible to pain, because the larger ones are unconnected with any nerve : hence the operation of the trepan has been performed upon sound persons, who were not un- der the influence of opium, with- out giving them any additional pain during the perforation of the skull. —See Fractures and Teeth. Decomposition of Bones. After being separated from the animal, they may be hardened and softened, both by acids and alkalies, accord- ing to the quantity of saline matter employed, and the manner in which i t i s applied. Although Bokrhaave asserts, that alkaline salts render them harder and furrier, and that acids make them softer and more flexible, yet these effects take place only in certain circumstances. Thus Newman found, that bones be- came harder and more compact by steeping them in oil of vitriol ; but BON when this acid was in sufficient proportion, it destroyed their co- hesion, and dissolved them. Dr. Lew i s, on die other hand, observed, that diluted vitriolic acid, though it rendered them remarkably soft, made them at the same timebrittle ; but that either in aqua fortis, or spirit of salt diluted, as well as in the acetous acid, they became flexi- ble and soft like leather. The most effectual and cheapest method of reducing the hardest bones to a soft pap or jelly, is that effected by the action of simple water, heated in what is called Papins Digester; a machine consisting of a strong and close iron vessel, in which the steam of boiling liquors is confined, and thus a more intense degree of heat is produced than any fluid could otherwise acquire. This effect, how- ever, may be accomplished in a much shorter time, when, instead of pure water, alkaline solutions are employed ; yet the latter could not properly be used in any culinary process. If bones be exposed to a mode- rate fire, either in open vessels, or in contact with the burning fuel, they become opaque, white, and friable : by increasing the fire, they are still more reduced, and easily crumble into a powder. But, if they be at first submitted to an in- tense heat, such as is required to melt copper or iron, they become firm, semi-transparent, and sono- rous, not unlike hard mineral stones. This curious experiment deserves the farther researches of the chemist. A method of producing phos- phorus in large quantities from bones, has been invented by M. Scheexe, who employed for this purpose the vitriolic acid: it has, therefore, been doubted, whether the