Page:Popular Science Monthly Volume 12.djvu/788

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THE POPULAR SCIENCE MONTHLY.

The Dean of Carlisle, Dr. Close, having made a violent attack on the practice of vivisection, denouncing it as a crime in the sight of that God "who careth for the sparrows," the Lancet very wittily retorts by quoting another Scriptural passage which the anti-vivisectionists are too prone to overlook: "Men are of more value than many sparrows."

Experiments made by Astasheffsky go to prove that the saliva of the rat possesses very strong diastatic activity—in other words, very rapidly converts starch into glucose; and that, as a general rule, the saliva of the rodents holds the foremost place as regards the mammalia; next comes that of the carnivora; and lastly that of the herbivora—the latter being decidedly the weakest of the three.

A writer in the School Journal would have all school chairs or seats on their front edge not more than one-quarter the height of the occupant, or of such a height that when sitting well back the heels of the sitter may touch the floor at a distance in front of the seat equal to the height of the seat. This it is claimed allows the point of support to be changed for the sake of comfort, and yet allows no unhealthy pressure. The width of the seat should equal its height; the slant should be about three-quarters of an inch to the foot; the surface should be flat. The back should be not less than one-tenth in excess of the height of the seat, so as to give full support to the shoulder-blades; it should slant about two and a half inches to the foot. The desk at the edge next the sitter should be five-thirds the height of the highest edge of the seat; its slant should be about one inch to the foot; its lower edge should stand directly above the front edge of the seat.

The cremation of the dead on battlefields is strongly advocated by Mr. William Eassie in an address to a sanitary congress in England. He is confident that by means of portable crematories he could reduce to ashes 10,000 bodies in as many minutes of time. Interment of bodies by thousands must of necessity pollute the springs and contaminate the air.

The building recently opened and dedicated in New York City for the use of the American Museum of Natural History consists of three stories, besides the basement and attic. These three stories constitute three halls, each 60 feet wide and 170 feet long, access being had by stairways in a tower at one end. The present building forms only a small part of a vast structure which it is designed to erect. The ground-plan of the future Museum may be described as a cross inclosed within a square. The portion of the structure now completed will form the northern end of the cross. The ground to be covered and inclosed by the buildings will be 850 feet in length by 650 feet in width.

A roof of zinc-coated sheet-iron, says the Polytechnic Review, does not wear out from oxidation, and does not crumble as does sheet-tin from the repeated contraction and expansion produced by changes of temperature. In Vienna and in Prague the manufacture of this roofing material is a growing industry.

The year 1877 showed a very considerable increase in the production of cocoon silk in France over the preceding year, viz.: in 1876 the product was 2,396,000 kilogrammes, but last year it was 6,783,000 kilogrammes. But this industry has yet to struggle hard if it is to attain in France its former condition, when the annual yield of cocoons was over 25,000,000 kilogrammes.

The leather covers of books in public libraries suffer very much from the action of the combustion-products of coal-gas. According to Prof. A. H. Church, vellum appears to be unaffected by this cause; but calf is much injured, and russia still more so. Most damage is done to the books in the upper shelves of a library, where the heated products of combustion are mostly condensed and absorbed. The sulphur of the gas is the principal cause of its destructive influence. Analysis of watery extract of leather injured by this cause showed that sulphuric acid, free and combined, was present in the proportion of 8.42 per cent.

The truth of the germ-theory of disease would seem to be demonstrated, at least with regard to one disease—splenic fever—by the researches of Dr. Koch. In cases of this disease, there accumulates in the blood and tissues, but especially in the spleen, a peculiar kind of bacteria—Bacillus anthracis. On inoculating animals with fluid containing either the bacilli themselves or their spores, Dr. Koch produced all the phenomena of splenic fever.

An Italian chemist, Paesi, proposes to substitute, for the tannin-bath in the manufacture of leather, a solution, in water, of perchloride of iron and common salt. Hides may be tanned, according to this process, in from four to six months. Moreover, the perchloride of iron, being a powerful disinfectant, does away with many objectionable features of the tanning business as hitherto conducted.