568 



THE POPULAR SCIENCE MONTHLY. 



exacts obedience to them at the cost of sick- 

 ness ; but, when these laws are obeyed, the 

 difference in the healthiness of climates 

 becomes comparatively insignificant. Euro- 

 peans 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 nat- 

 ure of what they eat, too often grant them- 

 selves the indulgences of rich viands, with 

 high seasonings and wines, which they en- 

 joyed at home. The mistake is even made of 

 increasing the quantity and richness of the 

 food, under the impression that the exhaus- 

 tion produced by the climate should be met 

 in that way, while a lighter diet is what is 

 really requirec^ 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 pre- 

 served his mind in a state of healthy vigor. 

 Other mistakes committed by European resi- 

 dents, which almost surely lead to disease, 

 are the excessive use of spirits dangerous 

 in the tropics above all other regions care- 

 lessness 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 

 v/hich is associated with Africa. Many of 



them are built near marshes or lacroons, in 

 the very worst places that could be selected, 

 such as would be pestilential spots any- 

 where, and they have been suffered to grow 

 up and accumulate nuisances without a 

 thought of the application of sanitary sci- 

 ence, 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 ac- 

 quire a crust, which impedes the rising of 

 the malarious vapors. " In the British pos- 

 sessions sucli 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 adopt- 

 ed by most Europeans in the tropics, so far 

 as they can be said to have any rule, ap- 

 pears 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 Mixtnres of Afriean 

 Races. Messrs. de Quatrefages and Hamy 

 have presented an important paper on the 

 craniology of the dolichocephalous negro 

 races. These races occupy the most con- 

 siderable part of the geographical area in- 

 habited by the negro race on the African 

 Continent. Regarded as a whole, they pre- 

 sent 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 con- 

 siderable limits. Consequently, they are di- 

 vided into a considerable number of groups 

 groups which are increasing. The Soo- 

 danian group, which presents the most com- 

 plete 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 Soo- 

 danians may be classified as eastern and 

 western. The cranial capacity of the west- 



