672 POPULAR SCIENCE MONTHLY. 



absence of crossing, as among the Jews * in the Bourbon Islands, f 

 with the Boers in South Africa, J and in many parts of South 

 America.* 



The physical elements of climate, ranged in the order of their 

 importance, are humidity, heat, and lack of variety. 



Heat by itself, when unaccompanied by excessive humidity, 

 does not seriously affect human health except when unduly ex- 

 tended. I The ranges of temperature to which the human body 

 may become accustomed are very broad, so that the limitations 

 to the dispersion of the race seem to be set by the food supply 

 rather than the degree of heat or cold."^ All authorities agree, 

 therefore, that the regions where acclimatization is most difficult 

 are to be found in the areas of excessive humidity, or, roughly, 

 where there is the maximum rainfall. ^ For this reason the suc- 

 cessful examples adduced in favor of the view that acclimatiza- 

 tion in the tropics is possible, should always be examined in the 

 light of this consideration. 



A traveler in northern Africa has noted this in his observa- 

 tion, that " where there is water and something can grow, there 

 the climate is murderous ; where the climate is healthy, there is 

 no water and nothing can grow." % In this sense, the boasted 

 acclimatization of the French in Algeria is merely accommoda- 

 tion to one element of climate, after all. With this limitation it 

 will be generally conceded that the success of the French in their 

 African possessions along the Mediterranean is assured. % The 

 mortality of soldiers and sailors in Algeria was seventy-seven 



* The Jews prosper in South America (Moutano, p. 445) and in Egypt (V^erhandhmgen 

 der Berliner Gesellschaft fiir Anthropologie, 1885, p. 258), and elsewhere (Jousset, p. 292); 

 while even in the uttermost parts of Russia they increase faster than the natives (Wallace, 

 op. cit.). Their cosmopolitan character, first pointed out by Boudin, is generally accepted 

 by anthropologists (Revue d' Anthropologie, new series, i, p. 76). Dr. Felkm suggests that 

 Semitic blood always helps in acclimatization (Scottish Geographical Magazine, vi, p. 662). 



f Quatrefages, p, 236. 

 \ Wallace, op. cit. 



* Ibid. 



II Jousset, p. 37 ; Ratzel, Anthropo-geographie, i, p. 308 ; Virchow in Verhandlungen 

 der Berliner Gesellschaft fiir Anthropologie, 1885, p. 208. 



^ Ratzel, op. cit.., p. 300, traces out the climatic limits of human life in detail. Vide 

 also Science, January 27, 1893. 



^ A comparison of Hahn's map of the extension of the plantation system in Petermann, 

 Geographische Mittheilungen, xxxviii. No. 1, p. 8, with a map of the distribution of rain- 

 fall m Berghaus's Physicalischer Hand Atlas will illustrate this relation. 



;|; Quoted from a scathing article by Max Nordau, Rabies Africana, in Asiatic Quar- 

 terly Review, second series, ii, p. 76. 



X General references are Berthelon, " De la Vitalite dos Races du Nord dans les Pays 

 chauds," and the statistics given by M. Bertherand (Paris, 1882). Vide also Landowsky 

 in Bulletin de 1' Association fran9aise pour I'Avancement des Sciences, Paris, 1878, p. 817. 



