Page:Popular Science Monthly Volume 17.djvu/589

Rh disease is quite different. Dr. Parkes names as the diseases of cattle that should be watched for: Pleuro-pneumonia, foot and-mouth disease; cattle-plague, or rinderpest; anthrax, or malignant pustule; simple inflammatory affections of the lungs; dropsical affections from kidney or heart disease; indigestion with apoplectic symptoms. The first three are described as contagious, and the last three as sporadic diseases, in a work by Professor Williams, of Edinburgh. To this list Mr. Hardwicke adds, as contagious, glanders and farcy (which may be communicated to consumers of horse-meat), puerperal apoplexy, and variola. He also adds a list of epizoötic diseases, meaning diseases occasioned by parasites, including measles in the pig; rot, or fluke disease, in sheep; gid, turn-sick, or staggers, in sheep; phthisis, or hoore, in cows, pigs, and poultry (gapes). The diseases of sheep are similar to those of cattle. They are subject to small-pox, malignant pustule, a parasitic chronic lung affection, and braxy or splenic apoplexy. Pigs are subject to anthrax, typhoid, and hog cholera. The contagious diseases are communicable by contact, by inoculation, and by infection. Hence it is not safe to let any of these classes of diseased meat go forth to the public as fit for consumption. To the opinion that cooking will destroy the contagious property and render the food fit for use, Mr. Hardwicke replies that there is no proof of it. Meat subjected to a temperature of 160°, which it is thought will thoroughly cook it, may still be productive of disease by inoculation. We are yet ignorant of the nature of the contagious property, and, if it be a living germ, what proof have we that, even if we succeed in destroying this germ and the entozoön of parasitic disease, a possible potent matter produced by the germ or ova of entozoon may not still exist and possess infective qualities?

The Milky Sea.—The peculiar coloration which has given the name of the milky sea to certain regions of the ocean has been remarked by many sailors, but a diversity of opinion has been expressed as to the cause of the phenomenon. Some have attributed it to electric action taking place during the hours preceding a storm; others to chemical combinations resulting from the decomposition of the bodies of marine animals and plants, and producing phosphorescence; others to spawn deposited on the surface of the water, which is supposed to be made to shine by the moving of masses of fish through it. None of these hypotheses have been confirmed, but they have all been contradicted by positive evidence that the milky sea is produced by a prodigious accumulation of animalcules, capable of becoming phosphorescent spontaneously, or of being made so by friction. The most recent and decisive evidence in this direction was observed on board the French ironclad Armida, on her recent voyage from Japan, while crossing from Point-de-Galle to Aden. At about half-past twelve in the morning of the 10th of February, 1880, the sky being clear, with no moon, the western part of the horizon, toward which the ship was going, became so bright as to attract the attention of the officer of the quarter. He at first thought the light was occasioned by the numerous bright stars which were about setting, but the increase of the light caused him to change his opinion, and he concluded that it was from a ship on fire. A half hour afterward a layer of whitish foam appeared covering the water for a considerable extent. The whole sea, shining with a milky luster as brightly as the usual phosphorescence which a ship produces in its passage through the water, resembled a field of snow in a clear night. It shone enough to efface all traces of the undulations of the swell; the waves could not be distinguished; and the sea seemed as flat and even as in a calm. The wake of the ship (which is generally visible for two or three miles back), and the disturbance of the water by the screw were hardly marked on the still surface. These facts proved that the luminous coating was not merely superficial, but that it had a considerable thickness. The phenomenon became more marked and intense, and one observing it might have believed he was locked in a sea of ice, had there been no movement of the ship to undeceive him. By daylight all had disappeared. On looking closely at the water as it rippled along the ship, there were noticed a great