280 THE PRESENT EVOLUTION OP MAN — PHYSICAL 



Even in countries where the pathogenic organisms are 

 most abundant they are not everywhere present, but 

 are more or less limited to crowded and ill-ventilated 

 domiciles to which infected persons have access. Indi- 

 vidual powers of resistance, even among peoples to which 

 the disease is quite strange, vary largely. Parties of 

 strangers from beyond the infected areas are therefore 

 never stricken down en masse, but one by one, at 

 different intervals ; and the symptoms noticeable in the 

 sufferers are such as are referable by unskilled 

 observers to other diseases — colds, coughs, &c. Last, 

 but not least — among the races which are least 

 resistant to malaria is our own ; on the other hand, it 

 is among the most resistant to tuberculosis ; and there- 

 fore our attention is not drawn, in the same marked 

 manner, to racial diff'erences in relation to the latter 

 disease as it is to differences in relation to the former. 

 We have all heard, for instance, of the sufferings from 

 malaria of our compatriots in India and on the West 

 Coast of Africa, and that in the year 1809 a British 

 army was, as a fighting force, destroyed by the same 

 cause in the Island of Walcheren, but few of us know, 



"That of 9000 Kaffirs (negroes from the East 

 Coast of Africa) who had been imported at various 

 times by the Dutch Government into Ceylon, and had 

 been drafted into regiments, scarcely a trace of their 

 descendants remains; they would certainly not be 

 recognized at all among the present population of the 

 island. In the years 1803 and 1810 the British 

 Government imported some three or four thousand 

 negroes from Mozambique into Ceylon to form into 

 regiments, and of these in December 1820 there were 

 left just 440, including the male descendants." — Hirsch, 

 vol. iii. p. 226. 



All the rest had perished, mainly from tuberculosis, 



