Page:Popular Science Monthly Volume 24.djvu/145

Rh contains, one of which is analogous to peptones and is a putrefacient, while the other is akin to globuline and is a much more fatal poison, probably attacking the respiratory centers and destroying the power of the blood to clot. The third proteid resembles the albumens, and is probably innocent. The poisons of the rattlesnake, copperhead, and moccasin are capable of being destroyed by bromine, iodine, bromohydric acid (thirty-three per cent), sodium hydrate, potassium hydrate, and potassium permanganate.

Antiseptic Qualities of Copper.—A few years ago copper was universally regarded as a deadly poison, and any questioning on the subject would, as M. Gautier observes, have been regarded as absurd. This opinion has been shaken by recent investigations. M. V. Burq claims for copper beneficial properties as a disinfectant and prophylactic. He has observed for thirty years that workmen in copper and players on musical instruments of brass, who were liable daily to absorb notable quantities of pure copper-dusts, enjoyed a remarkable immunity from infectious diseases. This was established in the case of the cholera in 1869 and 1873, during the epidemic which prevailed in Paris in 1876 and 1877, and in the recent visitation of typhoid fever, which was the immediate occasion of M. Burq's making a communication to the French Academy on the subject. M. Burq has been encouraged, by his own experiments and those of other physicians whom he cites, to recommend the administration of salts of copper as a preventive and remedy in cases of infectious disease. M. A. Gautier has recently published a book on "Copper and Lead in Food and Industry," in which he denies that copper is as dangerous a substance as it has been considered to be. Citing the observations of Burq, Galippe, and other authors, he discusses, in substantial agreement with them, the effect which copper has in industry and in general use upon workmen engaged with it, and upon public health. He represents it as a normal constituent in many of our foods. Wheat, barley, rice, beans, coffee, etc., constantly contain of it quantities varying from four to ten milligrammes per kilogramme. Prepared foods greened pickles, chocolate, etc. contain much more copper, from ten to two hundred milligrammes per kilogramme; and the author shows that, as a rule, we consume five milligrammes of metallic copper a day without receiving any serious injury from it. These quantities could be increased without much danger, but the taste of the salts of the metal is so disagreeable, and their color so conspicuous, that stronger doses would make the food nauseous and repulsive, so that the danger of one taking a fatal dose of copper is really quite remote. All food becomes uneatable when it contains four grammes per kilogramme of copper salts; even voluntary poisoning by copper is almost impossible. A practical inference from these observations would be, that the care we take to tin our copper cooking-vessels is useless. M. Gautier maintains, that it is even dangerous; for most tin contains lead, a deadly poison even in small doses; and it is this metal, in M. Gautier's opinion, that is guilty of the damage that has been attributed to copper. It meets us everywhere, and always leaves its mark in some damage to our system, slight in the detail, but cumulative in the aggregate. "We absorb it with our preserved foods, from glazed papers and oil-cloths, from paint, from enamels and crockery, from tin-ware, and from cosmetics, a little every day, till at last enough of the poison is accumulated in the system to make its strength very plainly felt.

How Raisins are dried.—Malaga raisins are made from two distinct kinds of grapes the Muscat, which is indigenous; and the Pero-Ximenes, which was imported from Germany two hundred or more years ago. Opinions differ concerning the respective merits of the two varieties. The vines are strongly manured, and are allowed to stretch themselves over the ground and absorb all atmospheric heat. The fruit is not all gathered at one time, but the same piece of ground is gone over three times, so that all the grapes may have the necessary ripeness. The raisins are prepared by washing, by drying by steam, or by simple drying in the sun. To dry the grapes by the washing method, furnaces of feeble draught are made in which wood is used as fuel. A round kettle of three or four hundred quarts' capacity