Page:Popular Science Monthly Volume 41.djvu/584

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568
THE POPULAR SCIENCE MONTHLY.

The swimming bladder of ordinary fishes has been modified so that it serves as a lung. In Africa, Protopterus, a form closely allied to Ceratodus, makes for itself a cocoon of mud, in which, during the hot, dry season, it lives, and can breathe by means of its lung. The Ceratodus does not appear to do this, and probably never leaves the water. It comes continually to the surface, and passes out and takes in air, making a faint spouting noise. The author suggested that the lung was of the greatest service to the animal, not during the hot but during the wet season, when the rivers are flooded and the water is thick with sand. The Ceratodus appears to be herbivorous, and feeds largely on the seeds of gum trees which fall into the water.

 

Dealing with Contagions.—A report by Dr. A. Jacobi calls attention to some peculiar difficulties in dealing with the contagion of scarlet fever and diphtheria. No general hospital must admit patients suffering from either disease. Hotel-keepers are not willing to admit them; but if cases get lodgment within their houses, it is to their interest to conceal the fact. Their interest, however, does not go so far as to induce them to destroy or disinfect curtains and carpets, and purify the walls of rooms, and the contagion is perpetuated. Rooms and suites of rooms in large and expensive hotels are known in which cases of diphtheria have occurred for several years in succession, all provoked by the same germ, lodged in the same curtains and carpets. The same danger lurks in private houses, where the well members are impei'iled by the presence of the sick one, and all the surroundings are liable to be infected; and in tenement-houses, where close contact of the well with the sick can hardly be avoided. Patients should be removed from homes and hotels and isolated; but this is impossible, for the want of provision for the proper care of such cases. The only institution for these diseases in New York is the Willard Parker Hospital, which is in a remote part of the city, and has beds for only seventy patients, while twenty-five hundred persons die annually of the infections. Plans for new hospitals are proposed by the Medical Society of the City of New York, and with them stations or refuges, where the children of families in which diphtheria or scarlet fever is prevailing can be housed until the patients at home have recovered or been removed, and their residences, bedding, and furniture have been thoroughly disinfected.

Treatment of Potato Disease.—The treatment of potato disease with sulphate of copper has been found efficacious at Nantes, France. A dressing of three pounds of sulphate of copper to twenty gallons of water, or of two pounds of sulphate of copper and four pounds of lime to twenty-five gallons of water, is used. The best results are obtained by using whole potatoes, sound, of medium size, selecting those which show the finest germs, and cutting very large ones in two. Before planting they are steeped for twentyfour hours in a bath composed of six pounds each of sulphate of ammonia and nitrate of potash and twenty-five gallons of water; then allowed to stand twenty-four hours to give the sprouts time to swell—whereby the growth is quickened and the return is increased. Disease in tubers is arrested by dipping them in a bath of water and as much lime as it will take, and drying them. The diseased part seems to solidify after this treatment, and does not spread, while the good part continues sound.

 

Propagation of Fine Flower Seeds.—From an address by Mr. George F. Daniels, quoted in Garden and Forest from the Journal of Horticulture, we learn that the increased demand for flowers in England and America has given a corresponding impetus to seed-growing abroad, where they have the advantage of cheap labor and a climate especially adapted to the work. The secret of successful cultivation in Germany lies in the bright, dry autumn, which enables seeds to stand longer and become more thoroughly ripened. The soil is also well adapted for the purpose. Stocks are one of the most expensive crops, in the item of labor, because the finer varieties have to be grown in pots, and they require attention in watering. China asters are grown by acres, one firm devoting more than a hundred acres to them. Petunias require much attention, as each bloom has to be fertilized by hand to insure the setting of the seed. The pollen from the double blooms is very difficult to obtain, the flowers being so dense that they have often