74

ELEMENTS OF MATEIilA MEDICA.

in the urethra, and sometimes strangury and bloody urine. Under theinfluence even of small doses of the oleo-resins the urine acquires aremarkable odour; and when any of the turpentines have been taken,it is that of violets. The mucous membranes generally are stimulated,and have their secretions diminished by the oleo-resins. We ob-serve this not only in the case of the urino-genital mucous membrane,but also in the membrane lining the air-passages. By the repeated useof the oleo-resins an eruption sometimes appears on the skin. In largedoses oil of turpentine causes an affection of the nervous system, whichwill be noticed hereafter.

The oleo-resins are principally employed in medicine to modifydiseases of the mucous membranes, especially that lining the urino-genital apparatus. Thus they are employed, and with great bene-fit, in gonorrhoea, leucorrhcca, gleet, and chronic catarrh of the bladder.In chronic pulmonary catarrhs they are sometimes advantageously em-ployed. Oil of turpentine has been used in neuralgia, against tapeworm, in puerperal peritonitis, and in other cases which will be noticedwhen speaking of that substance in a subsequent part of this work.

y. Balsams (balsama naturalia: balsams containing benzoic acid). —Theterm balsam was formerly applied to all liquid vegetable resins, as wellas to many pharmaceutical preparations. But to avoid confusion,the French chemists confine the term balsam to vegetable substancescomposed of resin and benzoic acid, with more or less volatile oil. Theobjection to this is, that the substances usually and popularly known bythe name of copaiva and Mecca balsams are, therefore, excluded fromthe list of balsams. Hence most of the German chemists retain the oldacceptation of the term, and divide balsams into those which do, andthose which do not, contain this acid.

Balsams (under which term I include those only which contain benzoicacid) are solid, soft, or liquid substances, according to the quantity ofvolatile oil which they contain : they have an aromatic, usually agreeable,odour, and a warm, acrid taste. They dissolve in alcohol; and thesolution, when mixed with water, becomes milky, owing to the deposi-tion of resin. By sublimation, as well as by other methods, they yieldbenzoic acid.

Those employed in medicine are benzoin, styrax, tolu, Peruvian bal-sam, and liquidambar. They are obtained from the orders Styracea;,Amyridaceoe, Kalsamacecu. They owe the principal part of their medicinalactivity to the contained benzoic acid. The liquid balsams (of styraxand Peru ) are sometimes applied to chronic indolent ulcers, to allay pain,to improve the quality of the secreted matter ( detergents ), and to promotecicatrization ( epulotics or cicatrisanlia). Taken internally the balsamsact as stimulants, their operation being principally directed to themucous membrane of the air-passages; on this account they are termedexpectorants, and are employed in chronic catarrhs. MM. Trousseauand Picloux (Traite de Therapeutique , t. i. p. 467) assert, from their ownexperience, that “ there are few substances in the materia medica sopowerful in combating chronic pulmonary catarrhs and old laryngealinflammations as the balsams.” In chronic inflammation of the larynx,whether accompanied or not by ulceration, balsamic fumigations aremore serviceable than the internal exhibition of the balsams. The air ofthe patient’s chamber may be impregnated with balsamic vapours by