350
ELEMENTS OF MATERIA MEDICA.
Berzelius ) acid, which combines with the undecomposed lime: so that theso-called chloride of lime is, according to this view, a mixture of chlorideof calcium and hypochlorite (or rather a tris-hypochlorite) of lime andwater. The following diagram illustrates the formation of these com-pounds according to the latter theory:—
REAGENTS.
2 eq. Chlorine,72.
C 1 eq.\ 1 eq.
Chlor. ..36-eq. Chlor... 36-xr 1 eq. Calcium20-
4 eq. Hydrate \ 1 eq. Oxyg.... 8—.—-1 eq. Hypochft.Acid 4
of Lime 144 < 3 eq. Lime .. 84--
* 4 eq. Water .. 36--
RESULTS.
•1 eq. Chloride Calcium= 56.
eq. Tris-hypochlorite
lima TOO
V * s
/3 a
When chloride of lime comes in contact with water, the tris-hypochloritedeposits two equivalents of hydrate of lime, while one equivalent of thechloride of calcium and one equivalent of the neutral hypochlorite oflime are dissolved.
The following table shews the composition of the so-called chloride oflime according to Soubeiran ( Nouv. Truitt: de Pharm. ii. 365); Phillips,(Transl. 3d ed.); and Ure, (op. cit.)
Soubeiran. ||
Eq.Eq.Wt.i
Chloride of Calcium .. .. 1 .. 56Tris -hypochlorite of Lime 1 .. 128Water. 4 .. 36
Phillips.
Eq. Eq.Wt.
Bihy drated Chloride of Lime 1 .. 82Lime .l .. 28
Chlorinated Lime. 1 ..110
Ure.
Ure's. Commer.
Chlorine..
. 40-31
.. 23
Lime
.. 45-40
.. 46
Water ..
.. 14-28
.. 31
_ £ 99 99
.. 100
Chi.orometry-— The chloride of lime of commerce varies in the quan-tity of hypochlorite which it contains, and hence some chlorometricalprocess is necessary in order to ascertain its goodness. The two princi-pal methods are, to determine the quantity of chlorine gas which itevolves on the addition of hydrochloric acid (Ure, Quart. Journ. of Sci-ence, xiii. 21) and to observe what quantity of sulphate of indigo it iscapable of decolorizing (Gay Lussac , in Alcock’s Essay, p. 136.) Dr.Ure says 10 grains of good bleaching powder should yield 3 or 4 cubicinches of chlorine.
Physiological Effects.— The effects of chloride (hypochlorite) oflime on the system have not as yet been accurately ascertained. Itslocal action is that of an irritant and caustic. A solution of it applied tosuppurating and mucous surfaces is a powerful desiccant, probably inpart at least from the uncombined lime in solution. When the secretionsare excessive and extremely fetid, it not only diminishes their quantitybut much improves their quality; so that considered in reference to sup-purating and mucous surfaces, it is not only a desiccant, but, in morbidconditions of these parts, a promoter of healthy secretion. Applied inthe form of ointment (composed of a drachm of chloride to an ounce offatty matter) to scrofulous swellings, Cima (Configliachi and Bmgnatelli’sGiornale di Fisica, 1825, quoted by Dierbach, d. neust. Entd. in d. Mat.Med. 1828, 2 te . Abt. 597), found that it provoked suppuration, causedstrong redness, promoted the suppurating process, and dispersed the sur-rounding hardness.
Taken internally in small doses (as from 3 to 6 grains dissolved in oneor two ounces of water) it sometimes causes pain and heat in the stomach,