320
ELEMENTS OF MATERIA MEDICA.
glass, which may be readily tinged by various metallic solutions,—thus,rose red by chloride of gold, and blue by solutions of cobalt; if a fewdrops of sulphuric acid be added to powdered borax, and then spirit ofwine, the latter will, when fired, burn with a green-coloured flame;lastly, if to a strong hot solution of borax, sulphuric acid be added, :boracic acid will be deposited in crystals, as the liquid cools. The testsnow mentioned for the most part only prove the salt to be a borate : thenature of the base is determinable by the tests for soda before described(p. 310).
Composition. —Chemists are not agreed as to the precise atomic con-stitution of borax, in consequence of a difference of opinion as to theequivalent of boron. In the following table the first column shows thenumber of equivalents according to Berzelius , Dumas, and Turner,—in jthe second, according to L. Gmelin, Brande, and Phillips.
Soda. 1 . . . 1 . . . . 32 ... . 16-666 .... 16 31 .... 17*8
Boracic Acid. 2 . . . 1 . . . . 70 ... . 36'458 .... 36'59 .... 35'6
Water. 10 ... 10 ... . 90 ... . 46-875 .... 47-10 .... 46 6
Crystallized Borax ... 1 . . . 1 .... 192 ... . 99"999 .... lOO'OO .... 100 0
By a particular management of the crystallizing process, Payen has -obtained borax in permanent octahedral crystals, containing only fiveequivalents of water. It is termed octahedral borax, in contra-distinctionto the ordinary kind, which is called prismatic borax. Octahedral boraxoffers several advantages to the arts over the prismatic variety (Guibourt,Hist, des Drog. t. i. p. 191, ed. 3 me .)
Physiological Effects. —The effects of borax have been imperfectlyascertained. Its local action is that of a mild irritant: applied to sores iit excites smarting, and taken into the stomach, in large doses, excites *vomiting.
The constitutional effects are probably those of a mild refrigerant anddiuretic. Wohler and Stehberger detected it in the urine, so that itpasses out of the system unchanged.
By some writers it is regarded as an agent exercising a specificinfluence over the uterus; promoting menstruation, alleviating the pain -which sometimes attends this process, facilitating parturition, diminish- iing the pain of accouchement, and favouring the expulsion of the iplacenta and lochia (Vogt’s Pharmakodynamik ). Further evidence, ,however, is wanting to enable us either to admit or deny the supposed -uterine influence of borax. Some recent English writers seem to enter- :tain no doubt as to its promoting uterine contractions (Dr. Copland, Diet ,of Tract. Med. art. Abortion, and Brit, and For. Med. Rev. for July 1838, jpage 86). |
Borax has also been regarded as producing the effects of alkalies on jthe system ; principally, I believe, from an erroneous notion that it was a jsuhsalt (Vogt, op. cit. and Sundelin, Heilmittellehre). When Homberg jasserted that boracic acid was a sedative, borax was supposed to possess jsimilar properties. '
Uses. —As a local agent, borax is employed, as a detergent, in aphtha Iand ulceration of the mouth. In some skin diseases it has been used >