months; Yakutsk suffers this mean temperature during December and January; Ustjansk, at the mouth of the Yana, only during January; while Tolstoi Noos, at the mouth of the Yenisei, lies entirely outside of the isotherm of -40°. The mean annual temperature of the Siberian cold-pole may be estimated at 2°. A still colder place appears to have been found by M. Klutschak, of Lieutenant Schwatka's expedition, at the Adelaide Peninsula, in Cockburn Bay, latitude 66° to 68°, where the temperature in January, 1880, reached -72°; in December, 1879, and February, 1880, -68°; and in September, October, and November, 1879, 5°, -38°, and -49° respectively. The mean temperature from December to February, -48°, varies but little from that of Werkojansk, and is from 18° to 21° lower than had been previously noticed in the American cold region.—Die Natur.
Do House-Flies convey Infection?—Dr. Thomas Taylor, of Washington, has published an account of some examinations he has made into the capacity of the common house-fly to transmit disease by carrying the germs from place to place. The question is really one of exceeding importance, for, "considering the habits and habitat of the house-fly, it will appear evident that, should it prove to be a carrier of poisonous bodies, its power to distribute them in human habitations is greater than that of any other known insect. Under our system of public travel, the common house-fly may be transported from one end of the continent to the other. It may feast to-day in the markets of Washington, and to-morrow in those of New York, and in a like manner it may be transported from a hospital for contagious or infectious diseases to homes in the vicinity, or even in remote localities. It may also be taken from one hospital to another, or from one ward to another within the same hospital, and may plant the germs of disease in exposed wounds, or deposit them in food, or liberate them in the atmosphere breathed by patients afflicted by diseases of a different class." Millions of the minute germs of putrefaction could be carried to a distant city by a single fly. These considerations justify and should prompt inquiry. Dr. Taylor's attention was called to the subject by his witnessing the sufferings of a fly afflicted with anguilulæ. In the direct experiments which were suggested to him by this observation, the larvæ of flies confined in a receiver with rust-spores ate the germs. When spores were sprinkled on sugar, the insects themselves consumed both spores and sugar; but some of the spores became fastened on the legs of the flies, and were only the more closely attached by the efforts made to get rid of them. They might, however, be brushed off by objects with which they were brought in contact, while their germinating powers would long outlast the life of the insect itself. Dr. Taylor regards it as evident from his experiments that flies are capable of conveying spores to plants and other bodies, but considers that the fact that the greater part of the spores were consumed by the flies or their larvæ shows that the insect may destroy microscopic germs as well as disseminate them, and indicates that in some cases its agency in keeping down their number may more than counterbalance its action in contributing to their dissemination.
American Stature.—Mr. George W. Peckham, teacher of biology in the Milwaukee High School, has been making investigations under the auspices of the Wisconsin State Board of Health into the growth of children. From examinations and measurements made chiefly in the schools of Milwaukee he has deduced the conclusion that the relative rate of growth of the sexes is such that the boys are taller till the twelfth year and heavier till the thirteenth, after which, between thirteen and fifteen the girls are both taller and heavier. After the age of fifteen, however, the boys exceed the girls both in weight and stature. Girls cease to grow when about seventeen years of age. Children of pure American descent are taller than children of foreign-born parents, but are generally lighter in weight than children of German parents. The children of Irish parents are also taller than those of German parents. Comparing his results with those of similar observations made in Boston, he concludes that school-children in Milwaukee are taller than those in Boston, and the boys weigh more, but the girls of Boston are slightly heavier than those of Milwaukee. The su
