Unfortunately, the action of climate upon a man taken from his own country is not merely a case of sun-burn. And medical statistics have shown, in treating on the different races of mankind, the dangers of changing one’s position on the surface of the globe, even if it takes place in the sense of isothermal lines. We find from the results of careful inquiries made in the English colonies at the Antilles for about forty years, that the black population is continually diminishing, the number of deaths being to that of births :: 28 : 24. Under the tropics, northern organisations are much disquieted, life changes its aspect, and its course is much more rapid. The glandular system governs;[235] man becomes “more sensible to pleasure, and less disposed to activity,”[236] his mind loses its vivacity. Those noble faculties, which have made the white man the monarch of creation, become weakened, and that especially in some colonies where government is obliged to entrust everything to Europeans.[237] Dr. Barnard Davis lately announced to the Paris Anthropological Society,[238] that one of his friends, Dr. J. A. Wise, after thirty years residence in India, had never been able, after numerous inquiries, to find any descendants of a European in the third generation. Our temperate regions are to the Negro what the tropical zone is to the European. Even at Gibraltar,[239] the Negro contingent that was employed in the English army paid a heavy tribute to death.[240] On the contrary, official documents for 1861 tell us that, at Sierra Leone,[241] the respective mortality of English and Negro soldiers was as follows:-- Deaths per 1000. English. Negroes. Marsh fevers 410·2 2·4 Dysentery 41·3 5·3 Liver disease 6·0 1·1 It is an indubitable fact that, in general, the mortality of an emigrated population is in an inverse ratio to the distance they are taken.[242] During many years the island of Ceylon was occupied by Hindú troops (from Madras and Bengal), Malays, Negroes and English. The mortality of these races respectively was, 12, 24, 50, and 69. This is so clearly a biological law, that we again meet with its application even in certain particular cases. Concerning the yellow fever, for instance, Townsend has thus laid down a rule,--“The mortality to the new-comer from the cooler latitudes may be said to be in an exact ratio to the distance from the equator of his place of nativity.”[243] Daniel Blair[244] has given the following statistics, according to his observations of the same disease, made in British Guiana, from 1827 to 1835:-- Natives (West Indian Islanders) 6·9 French and Italians 17·1 English, Scotch, and Irish 19·3 Germans and Dutch 20·2 Scandinavians and Russians 27·7