regard to some writers, that the temptation to be picturesque 

 rather than to be strictly accurate must be considerable. 

 If man originally came from the tropics, we may assume 

 that his physical environment was then suitable, and that 

 time must have been a very important element in connec- 

 tion with his gradual adaptation to new conditions in sub- 

 tropical, temperate, and finally the colder regions and 

 snowy deserts of the earth. Herbert Spencer in his "Study 

 of Sociology," says with regard to climatic changes of 

 constitution, that "such changes can be brought about 

 by slow spreadings of the race through intermediate regions 

 having intermediate climates to which succeeding genera- 

 tions are accustomed little by little." Surely the conditions 

 of peopling the cold regions by colonising races must have 

 originally been as difficult as the task is now said to be of 

 peopling the tropics with the white races. For fears are 

 even now expressed that in Canada and Russia the long 

 continued cold conditions in w r inter seriously militate 

 against the white races, since man needs so much and 

 nature is so inhospitable, and plant and animal life so 

 restricted, that his utmost activity is necessary so that he 



Tropical Diseases.— It may be admitted that natives of 

 tropical countries are not injured by the sustained high 

 atmospherical temperature in which they live, as their 

 physical activity is attuned by custom and habit to their 

 surroundings. A European requires to adjust himself to 

 altered meteorological conditions. But, as Sir Patrick 

 Manson, an eminent mediea.1 aut liorit.y. Ims [minted out : — 



in the native alike, nearly all disease is of specific origin." 



Germs of a parasitic nature are the source of nearly all 

 disease, but these require certain conditions of temperature, 

 certain media, and certain opportunities for their continued 



