REPORT OF CHEMIST. ALFRED W. PERRY, M. D. OFFICE OF CHEMIST, New Orleans, La., Dec. 31st, 1872. Having been assigned to the duty of making any scientific investigations which might be required for the use of the Board of Health, I herewith present my report of the work done in the laboratory of the Board of Health, for the year 1872. J. R. TERRY'S ZINC-IRON DISINFECTANT. This consists of a clear green liquid, containing a small sediment of peroxide of iron, with about twenty per cent. of its bulk of crude carbolic acid, floating at its surface. The green liquid contains fourteen per cent. by weight of copperas, or proto sulphate of iron, with a trace of sulphate of zinc. One gallon of this fluid would contain about one and one-seventh pounds of copperas; it therefore has less than one-twentieth of the disinfecting power of the zinc-iron solution, prepared according to the formula published by the Board of Health. EFFECT OF CARBOLIC ACID VAPOR ON SUGAR. In view of the possible use of carbolic acid in disinfecting vessels arriving at the port of New Orleans from places infected with yellow fever, I have made, at your suggestion, some experiments, to see if sugar exposed to an atmosphere charged with carbolic acid would absorb enough to damage it. A loose wooden box containing a few pounds of yellow sugar was exposed five days, in a close, small room, in which several shallow vessels containing crude carbolic acid were placed, as a result of which the air was very strongly impregnated with the vapor of the acid. A part of the sugar was taken out every day, and compared with some of the same sugar which had not been exposed to the vapors of the acid. No difference in smell, taste or color could be distinguished. From this result I am satisfied that carbolic acid vapor may be used in disinfecting a sugar-laden vessel (as those arriving from Cuba usually are), in sufficient quantity to destroy any disease germ, and yet do no damage to the cargo. DE WESSERLY'S SOLUTION OF CHLORIDE OF IRON. This liquid has a high specific gravity, 1.42, corresponding to 43 deg. Baumé. It contains in 1 litre or 1000 grammes by measure, 322 grammes of chloride of zinc, 230 grammes of proto-chloride of iron. The chloride of zinc is a very valuable disinfectant for destroying sulphuret of ammonia and other compounds, which are injurious to health. The reason why it has not been used more is, that when prepared directly, it is more expensive than the per-chloride of iron. It is far more efficient as a disinfectant than any of the salts of iron; and now, that by reason of being a waste product in certain manufacturing processes, it can compete in price with the per-chloride of iron, it deserves the preference for use in privies, gutters, drains, etc. The iron which this liquid contains is entirely in the state of proto-chloride, and acts just as copperas does, only on sulphur when in an alkaline combination; it has no action on free sulphuretted hydrogen. The chloride of zinc does not act on sulphuretted hydrogen. At a price of fifty to seventy-five cents per gallon, it is the cheapest disinfectant that can be used; but it does not act on free sulphuretted hydrogen, as I found by actual experiment. In order to secure its action on this gas, I recommended that the proto-chloride of iron should be converted into per-chloride of iron, which is cheaply done Es besting the liquid with nitrate of soda and muriatic acid. sofacitly recommended by the Board of Health as "Zinc BROMO-CHLORALUM. und Moralum, given to me by the agent at to consist almost entirely of a asa math #k" aluminium, with small quantities of chloride of calcium, magnesium, sodium and iron, which were probably accidental impurities; it also contained 30 grains of bromine per pint, combined with sodium; it contained no free bromine. In some experiments which I made with bromochloralum, to determine its practical effect in deodorizing the offensive sulphur compounds, I added fifty per cent. of bromochloralum to 1 oz. of sulphuret of ammonium; in neither case was the odor destroyed, while half of one per cent. of a saturated solution of sesqui-oxide of iron in muriatic acid, completely and immediately destroyed the ordor of the sulphuretted hydrogen water, and seven per cent. of the iron solution destroyed the odor of the sulphide of ammonium. From this it will be seen that this preparation of bromo-chloralum has no practical value in destroying the offensive products of animal and vegetable decomposition, which are principally sulphur compounds. It will undoubtedly prevent decomposition in animal fluids, and as such, is valuable as a dressing for foul ulcers, wounds, sores, etc. EGYPTIAN DISINFECTANT POWDER. Tenny's disfectant powder, presented to the Board of Health for examination, was examined, and found to consist of dried. powdered clay, mixed with 23 per cent. of carbolic acid, and 7-10 of one per cent. of sesqui-oxide of iron. One hundred pounds of this powder, would contain two and a half pounds of carbolic acid, worth not more than twenty-five cents, and the oxide of iron almost nothing. This powder has very little practical effect as a disinfectant. I found that a solution of sulphide of ammonium, was not deodorized by less than five times its weight of this disinfecting powder. In making this disinfecting powder the iron is added as sulphate of iron, but lime is also mixed with the powder, which changes the sulphate of iron into the valueless oxide of iron. THE CAUSE AND AMOUNT OF IMPURITIES IN THE AIR OF LARGE CITIES. The system of removing offal and all organic refuse from this city is so manifestly imperfect, and the injurious effect on the public health of so much decomposing animal and vegetable matter is so obvious, that perhaps some excuse is needed for bringing forward any proofs of it. In the series of investigations which I have made, the object has been to fix definitely the extent of the injurious effects (chiefly air and water pollu tion) of non-removal of offal from the midst of our city. From three-fourths of the houses in the city, the solid offal is removed pretty regularly by the offal carts. The offal from the other fourth is thrown into the streets and gutters. All the liquid and semi-liquid refuse, slops, etc., are allowed to run into the gutters, in seven-eighths of which they remain. It is only in those streets of the Second, and some of the First District which are perpendicular to the river, that there exists a sufficiently strong flow of water to carry off the liquid offal which is thrown into them. This organic matter remains in the gutters until scraped out, and spread on the street; the first rain washes it back into the gutters again, and thus it is constantly decomposing and giving off unwholesome vapors. The quality and amount of the putrifiable substances which exist in the semi-fluid mud of some of the stagnant gutters of our city, are shown by the following analyses. The amount of decomposing substances found is, in the aggregate, truly appalling to persons who value health and comfort. A sample of mud, weighing 1000 grains, was evaporated to dryness and found to contain 24 per cent. of solid matter. During the evaporation there was evolved fifteen one-hundredths of a grain of ammonia, which had been produced by the previous decomposition of seventy-six one-hundredths grains of animal matter, and which had not yet escaped into the air. A small quantity of the dry residue was ignited in a combustion tube with soda-lime, and produced 88-100 of 1 per cent. of ammonia, which showed the presence of four and one-half per cent, of animal matter. Another small weighed quantity of the dry residue was ignited in a platinum crucible, and showed by the loss that it contained 29.5 per cent. of vegetable matter. A gutter the length of one square, say 300 feet, 3 inches deep and 15 inches wide, contains about six thousand pounds of semi-fluid mud, of which twentythree per cent. dry residue makes 1400 pounds of solid matter. This, by the figures of the above analysis, contains 63 pounds of animal matter and 420 pounds of vegetable matter. Four different samples of foul mud were examined, with the following results: All this vegetable and animal matter when exposed to summer heat and moisture, is almost entirely resolved by decay into gaseous or volatile substances which escape into the air, and are constantly being inhaled into our lungs. The soluble portions of this organic matter are to some extent washed into the ground by the rains, and this gives rise to a pollution of the sub-soil water. The extent of this is shown by the subjoined table of analyses of shallow well waters, which were made in May and June. Analysis of Water from Shallow, Unused Wells-Sub-soil Water in Milligrammes per Litre, or parts per 1,000,000. Ammonia. Nitric Acid. No. 1 well, corner of Love and Marigny, three feet from 179 Enghein, six feet from brink of privy vault. privy.. 139 Josephine street, ten feet from wooden privy.. Berlin and Camp, twenty feet from privy vault... 604 456 331 2 20. 5 5 90 720 Annunciation, near Camp, twelve feet from wooden privy.. 46 19 389 privy... 59 Rousseau, eighteen feet from leaking privy.. 28 9 84 800 1 18208 1200 |