Page:Popular Science Monthly Volume 31.djvu/151

Rh the mass of the water and its equatorial situation, that it is so healthy as it really is. Some of the tributaries of the Amazon are very insalubrious, and life anywhere in them, in any condition, is made miserable by insect pests; yet Mr. Wells has never met any one, who has had an experience of life on the Amazons, who has not become passionately fond of it. "The glorious vegetation, the life free from conventionalities, and the brilliant sunlight and warmth, tempered by fresh breezes, contain some of the elements of making a paradise," and numerous lines of river-steamers afford means of convenient communication. The vegetation of this great valley is essentially different from that of the other two riverine systems. The rich, low-lying lands, subject to annual inundations, frequent rains all the year, and the continual heat, produce a vast wealth of dense tropical verdure, and a forest area greater than can be found in any other part of the globe, intersected by thousands of miles of immense navigable streams, give the region a unique character. Among the valuable vegetable productions, the India-rubber tree figures pre-eminently. It exists in such vast numbers, and the collection of the juice is so very lucrative, that it has attracted to even the most remote rivers thousands of adventurous Brazilians from the adjoining provinces, and it is doing for the Amazons what gold did for Australia and California.

The Microbe of Malaria.—Dr. George M. Sternberg has communicated to the Scientific Association of Johns Hopkins University an account of the confirmation, by his own observation, of Laveran's discovery of the germ, or micro-organism, of malaria. Laveran found this microbe in the shape of an amœboid parasite, in the blood of patients suffering from fever; and also observed that the germs disappeared from the blood when quinine was administered in effective doses. His observations were confirmed by Richard, in 1882, and by Marchiafara and Celli from their researches in the Santo Spirito Hospital of Rome. During a recent visit to Rome, Dr. Sternberg accompanied these gentlemen to the Santo Spirito Hospital, where a most satisfactory demonstration was made to him of the presence and amœboid movements of the parasite, in blood drawn from the finger of a patient in the first stage of a malarial paroxysm. Marchiafara and Celli have induced types of intermittent fever, in previously healthy persons, by injecting into the circulation a small quantity of blood drawn from a malarial patient during his fever. The presence of the parasite in the injected blood was demonstrated, and it was found again in the blood of the persons subjected to the experiment during the induced intermittent paroxysms. These paroxysms were arrested, and the parasite disappeared from the blood when quinine was administered.

Systematic Observations of the Aurora Borealis.—No country is more favorably situated for the systematic observation of the phenomena of terrestrial magnetism and the aurora borealis than Norway. Extending from the fifty-eighth to the seventy-first degree of latitude, it reaches farther north than any other inhabited land, and lies nearer to the center of magnetic disturbances than any other state of Europe. The maximum zone of the northern lights hangs over the northern and northwestern part of the land. The northern and southern districts are connected by numerous telegraph lines and through the telephone exchanges of Drontheim and Bergen. Sophus Tromholt began to organize a system of investigations in 1878, and from September of that year to April, 1879, he recorded 839 observations of 154 northern lights. His idea met with favor, and the method of concerted observation has spread since that time to Sweden, Denmark, and Finland, England, Greenland, and Iceland. The observations of the winter of 1879-80 were much more extensive than those of the previous winter, being 1,600 in number of 249 auroras at 357 stations. In the winter of 1880-81, 5,200 observations were made of about 300 auroras, at 675 stations; and in the winter of 1882-'83, 1,500 persons in the North European countries participated in the work. Notices are now regularly transmitted from fifty Swedish and Norwegian telegraphic stations of all electrical disturbances, with exact minutes of time, direction, etc.; observations that are of the more importance, because not a day passes