In the first place, contrary to the general opinion, condensed steam does not always furnish pure distilled water. The drip from the cylinders of steam engines is never fit for use, not being half so good as ordinary rainwater. In preparing dis-tilled water, the directions generally given to reject the portion that first comes over should never be omitted.
The best water from which to prepare the distilled article is, in my opinion, good clear well water. Rainwater is generally well loaded with organic matter, and holds generous quantities of ammonia in solution. Ammonia, of course, distils over, and this impurity the Pharmacopoeia does not permit. Prof. Lloyd once said that' in order to prepare an acceptable article of distilled water from the city at Cincinnati, it was necessary to distil 3 to 4 times from an ordinary apparatus; but that now, by carrying a stand pipe to the third storey of his factory, the product obtained was good.
The following procedure in distilling and storing will never fail to give satisfaction. Say the still is of 5 gal. capacity, not more than 4 should fever be distilled therein: take then 4 1/4gal. of good clear well water; boil violently in a bright tin vessel for 10 minutes - this drives off almost the last trace of ammonia; then introduce into the perfectly clean still; start. the process; reject the first 1/2 gal., and save the succeeding 2 1/2 gal.
This is to be stored as follows: Prepare an empty carboy by boring with a rat-tail file a hole in the solder: through this hole introduce a glass siphon, made air-tight at the point of contact with the carboy by slipping over the siphon tube a piece of rubber tubing, and on the longer arm of the siphon place another piece of rubber tubing about 4 in. long, provided with a pinchcock. Into the mouth of the carboy fit a perforated cork, holding a glass tube filled with cotton; this is to be inserted as a stopper, the tube filled with cotton acting as a vent. All the air entering the carboy will be drawn through the cotton, thus being filtered perfectly free from motes. It is these motes, or dust particles, among which the seeds of the conferva exist that cause the ropiness which is to be avoided.
The distilled water in dropping from the mouth of the condenser into the receiver, as a rule, becomes contaminated with air motes, and unless these be removed before the water is finally deposited in the carboy, confervoid growths will appear.
To accomplish this, the distilled water must be brought to a boil in a bright tin vessel, the warm carboy thoroughly rinsed with it, and when, at last, the container is full, insert'the perforated stopper carrying the tube filled with cotton; start the siphon, and now, if the stopper is not removed, the entire contents may be used, as required, and not a single fleck will form therein. (J. N. Hurty.)
Boracic acid only acts when present in large quantity. It prevents the growth and multiplication of germs, but does not kill them even in a 1 per cent, solution. Experiments with milk gave very unsatisfactory results, as an addition of 4 per cent, boracic acid only preserved the milk for 4 days. Horseflesh may be preserved for 6 weeks by the use of 3 per cent, of the acid. Boracic acid is supposed to be harmless, but recent investigators prove it to be dangerous, as it strongly acts upon the mucous membrane of the large intestine. A dose of 4 grin, killed a large rabbit; 2 grm. made a dog very sick. The acid is much used in Sweden for preserving fish and milk, but cases of poisoning have already occurred in that country. Long continued use of the acid is not favourable to good health, and at all events its addition to milk should be prohibited. (Emmerich.)
"Adulteration " with Boracic Acid.- - The increasing use of boracic acid, as well as of other so-called antiseptic agents for the preservation of articles of food, is a matter which demands immediate and most serious attention. Boracic acid is generally added to milk and cream in the form of certain proprietary articles, which are sold to the trade under different fancy names. Some of the more commonly used preparations, which consist'of a mixture of boric acid (partly anhydrous and partly hydrated) with borate of soda, are added (in solution) in the proportion of at least 7 gr. of the solid substance to 1 pint of milk. In cream, it is generally added in at least double this quantity per pint. Inasmuch as both the farmer in the country and the dairyman in the town are likely to use these preparations, these amounts may be largely increased. The amounts mentioned are also very likely to be exceeded through the carelessness or Ignorance of those making use of such substances for preserving purposes.
But scanty information is to be obtained as to the action of boracic acid and borates on the human subject. These substances do not appear to have been much used as internal remedies, and, accordingly, but little information as to their action is to be found in the text-book 8. One authority states fiat borax acts as a mild alkali on the alimentary canal; tending to render the fluids alkaline, and to cause diuresis; that it checks fermentation due to organisms, and is used as a diuretic and antacid. Another eminent authority who was consulted in connection with the report previously alluded to refers to the tendency of these substances to set up diarrhoea, a disease very prevalent in hot weather, when the preservatives are most used to prevent the change which milk and cream are apt to undergo rapidly at a high atmospheric temperature. The medicinal dose of the acid as laid down in the British Pharmacopoeia for' an adult ranges from 5 to 30 gr., and, on the authority of Dr. Dudfield, and of others, it may be computed that 1/12 of the quantity, say a maximum of 2 1/2 gr. would be a suitable dose for a child under one year.