[161] An attempt has been made by Besnou to estimate the amount of alcohol by the specific gravity. He found that a chloroform of 1·4945 gravity, mixed with 5 per cent. of alcohol, gave a specific gravity of 1·4772; 10 per cent., 1·4602; 20 per cent., 1·4262; and 25 per cent., 1·4090. It would, therefore, seem that every percentage of alcohol lowers the gravity by ·0034. Dr. Dott, _Pharm. Journ._, 1894, p. 629, gives the following tests:--Specific gravity, 1·490 to 1·495. On allowing ½ fluid drm. to evaporate from a clean surface, no foreign odour is perceptible at any stage of the evaporation. When 1 fluid drm. is agitated with an equal volume of solution of silver nitrate, no precipitate or turbidity is produced after standing for five minutes. On shaking up the chloroform with half its volume of distilled water, the water should not redden litmus-paper. When shaken with an equal volume of sulphuric acid, little or no colour should be imparted to the acid. § 175. The ordinary method of manufacturing chloroform is by distilling alcohol with chlorinated lime; but another mode is now much in use--viz., the decomposition of chloral hydrate. By distilling it with a weak alkali, this process yields such a pure chloroform, that, for medicinal purposes, it should supersede every other. Poisonous Effects of Chloroform. 1. AS A LIQUID. § 176. =Statistics.=--Falck finds recorded in medical literature 27 cases of poisoning by chloroform having been swallowed--of these 15 were men, 9 were women, and 3 children. Eighteen of the cases were suicidal, and 10 of the 18 died; the remainder took the liquid by mistake. § 177. =Local Action of Chloroform.=--When applied to the skin or mucous membranes in such a way that the fluid cannot evaporate--as, for example, by means of a cloth steeped in chloroform laid on the bare skin, and covered over with some impervious material--there is a burning sensation, which soon ceases, and leaves the part anæsthetised, while the skin, at the same time, is reddened and sometimes even blistered.