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ELEMENTS OF MATERIA MEDICA,
Composition. —The following is the composition of lime and itshydrate: —
Calcium .. .. 1 .. .. 20 .. .. 71’42 .. .. 71-91 II Lime .. .. 1 .. .. 28 .. .. 75-67
Oxygen .. .. 1 .. .. 8 .. 28-57 -. -. 28-09 || Water .. .. 1 .. .. 9 .. 24-32
Lime. 1 .... 28 .... 99'99 .. ..~100'00 || Hydrate of Lime 1 .. .. 37 .... 99’99
Purity. —The lime used in the arts is never absolutely pure, butusually contains variable quantities of carbonate of lime, silica, alumina,and oxide of iron, and sometimes magnesia.
Physiological Effects, (a.) On vegetables ,—Quicklime is poisonousto plants. Notwithstanding this, however, it is sometimes used as amanure, its efficacy depending on its decomposing and rendering solublethe vegetable matter of the soil, during which the lime attracts carbonicacid and becomes innocuous. (Davy, Agricult. Chemistry .)
(b.) On animals. —On dogs, Orfila ( Toxicol. Gen.) found that quicklimeacted as a caustic poison, but not very energetically ; and that it occa-sions death by producing inflammation of the texture with which it comesin contact.
(c.) On man. —Quicklime is an escharotic. Its chemical action on thetissues is analogous to that of the fixed alkalies, to which must be addedits powerful affinity for water. Its use in promoting the decompositionof the bodies of persons who have died of contagious diseases, or on thefield of battle, and its employment by the tanner to separate the cuticleand hair from skins, sufficiently establish its causticity. Its escharoticand irritant action is well seen in the ophthalmia produced by thelodgment of small particles of lime in the eye.
When applied to suppurating or mucous surfaces, lime water cheeks orstops secretion, and produces dryness of the part: hence it is termed adesiccant.
When administered internally, it neutralizes the free acid of the gastricjuice, diminishes the secretions of the gastro-intestinal membrane, andthereby occasions thirst and constipation. It frequently gives rise touneasiness of stomach, disordered digestion, and not unfroquently tovomiting. After its absorption it increases the secretion of urine, anddiminishes the excessive formation or deposition of uric acid and theurates. With this exception, it does not, as the alkalies, promote theaction of the different secreting organs, but, on the other hand, diminishesit, and has in consequence been termed an astringent. But it does notpossess the corrugating action of the astringent vegetables, or of many ofthe metallic salts : it is rather a drying remedy, and might be more cor-rectly termed a desiccant than astringent. In this respect lime differsfrom the alkalies, but is analogous to the oxide of zinc. Vogt ( Pharmak.)considers it to be intermediate between the two. Weickard andothers have ascribed to lime an antispasmodic property ; and if this betrue, its relation to zinc is still further proved.
A power of exciting and changing the mode of action of the absorbentvessels and glands has been ascribed to lime water, and probably withfoundation. At any rate, under the use of it, glandular enlargementshave become softer and smaller. Sundelin ( Heilmittell.) says that theexcessive use of lime does not, as in the case of the alkalies, bring abouta scorbutic diathesis, but a general drying and constriction, analogous tothat caused by zinc.