exacts obedience to them at the cost of sickness; but, when these laws are obeyed, the difference in the healthiness of climates becomes comparatively insignificant. Europeans going to tropical countries are apt to neglect the precautions with reference to food which the changed conditions of their life would require them to take, and, instead of reducing the quality and varying the nature of what they eat, too often grant themselves the indulgences of rich viands, with high seasonings and wines, which they enjoyed at home. The mistake is even made of increasing the quantity and richness of the food, under the impression that the exhaustion produced by the climate should be met in that way, while a lighter diet is what is really required. The stomach can not bear the burden imposed upon it, and symptoms of disease arise. The loss of memory and mental capacity, which have been remarked as effects of a long residence in the tropics, are partly due to tropical heat, but far more to the solitude, with insufficient variety of incident, and the want of mental exercise, to which residents are exposed by the lack of society and of the distractions which society promotes. "Europeans in Africa do little else than eat and drink, rest and sleep," will seek for nothing to occupy their minds, and will often sit listlessly for hours gazing at vacancy. Consequently the mind is apt, from want of judicious exercise, to sink gradually, and the man to fall into apathy. In such a condition he is far more liable to an attack of fever than one who has preserved his mind in a state of healthy vigor. Other mistakes committed by European residents, which almost surely lead to disease, are the excessive use of spirits—dangerous in the tropics above all other regions—carelessness in regard to exposure, and neglect of exercise. More or less of exposure to the atmospheric changes of the country is inevitable, and the body that is prepared to withstand them is in less danger from them than are the too sensitive organizations of those who take too much care of themselves. This preparation can be gained by judicious exercise at different periods of the day and year. The bad location, and neglect of the sanitary condition of the coast towns, are responsible for much of the unhealthiness which is associated with Africa. Many of them are built near marshes or lagoons, in the very worst places that could be selected, such as would be pestilential spots anywhere, and they have been suffered to grow up and accumulate nuisances without a thought of the application of sanitary science, which seems to be wholly unknown, to their improvement. The natives have an effectual means of warding off malaria by planting groves of trees between the swamps and their villages, or by burning the bush and allowing the soil exposed thereby to acquire a crust, which impedes the rising of the malarious vapors. "In the British possessions such obvious means of protection appear to be either unknown or despised." The rule of life Mr. Mitchinson would lay down for a resident in the tropics is based upon the words "diet, exercise, and energy." These, he says, are the man's climate, his life, the power of the intellect nourished by the normal blood. "The rule of life adopted by most Europeans in the tropics, so far as they can be said to have any rule, appears to be 'feed and rest, rest and feed"; few give any intelligent consideration to the subject of the preservation of health." It is no wonder, then, that European residents die early.
Movements and Mixtures of African Races.—Messrs. de Quatrefages and Hamy have presented an important paper on the craniology of the dolichocephalous negro races. These races occupy the most considerable part of the geographical area inhabited by the negro race on the African Continent. Regarded as a whole, they present a considerable homogeneity in the most essential characteristics; but differences of habitat and the mixture of foreign elements Lave caused their secondary characters, both exterior and anatomical, to vary within considerable limits. Consequently, they are divided into a considerable number of groups—groups which are increasing. The Soodanian group, which presents the most complete exemplification of the general type, occupies all the space comprised between the Sahara on the north, Senegambia on the west, Guinea on the south, and the valley of the upper Nile on the east. The Soodanians may be classified as eastern and western. The cranial capacity of the west-
