148 THE PRINCIPLES OF HEREDITY 



respect to the great frequency of phthisis among them. In 

 Northern Greenland that disease is one of the commonest 

 causes of death. At a trading station on the northern shore 

 of Hudson's Bay phthisis is prevalent among the scanty 

 population to an enormous extent, according to the evidence 

 of a practitioner who had been five years on the station, and 

 there are reports to the same effect from New Archangel and 

 the Aleutian Islands (Alaska). It is common also in New- 

 foundland, New Brunswick, and Canada, and in the last 

 particularly among the native Indians (Stretton)." 1 



243. Just as regards malaria, so as regards tuberculosis, 

 the resisting power of any race is precisely in proportion to 

 its past familiarity with the disease. 2 Many writers lay 

 stress on the susceptibility of Africans, as may be seen from 

 the following: "No race or nationality enjoys a decided 

 immunity from consumption ; but in respect to the frequency 

 of its incidence, the Negro race takes the first place. Proof 

 of this is furnished by the medical reports from all those 

 parts of the world to which the Negro has migrated, and in 

 the mixed populations of which he forms a large ingredient : 

 such as the United States, the West Indies, the Mosquito 

 Coast, Brazil, the Argentine Kepublic, Peru and Bolivia, 

 Algiers, Egypt, the West African Islands, Ceylon and the 

 East Indies. 



244. " In the convict prison of the United States, from 

 1828 to 1845, the average mortality among the prisoners of 

 the whites was 11*16 per 1,000 ; but among the Negroes 

 confined in the Eastern Penitentiary of Pennsylvania it was 



1 Hirsch, vol. iii., pp. 182-3. 



2 It has been said that blonde people are particularly susceptible to 

 tuberculosis. This may be true of our race, though that is more than 

 doubtful. The notion may have arisen from the fact that fair skins 

 show a hectic flush very plainly. It is certainly not true of mankind at 

 large. Some of the darkest races of the world are very susceptible. 

 Colour, in fact, appears not to be correlated in any way to susceptibility. 

 Had it been so all races which have been much afflicted by phthisis 

 would now present a particular shade of colour. It is probable, there- 

 fore, that the so-called " phthisical facies " is a consequent not a precedent 

 of the disease. Again, it has been said that vulnerability to phthisis 

 " resides in the epithetal coverings of the body being too little resistant, 

 too easily stimulated by external agencies, too readily penetrated by the 

 parasites of the disease." But this is a manifest error. It is not probable 

 that all the races of the New World are weaker as regards the epithetal 

 coverings than, for example, Englishmen. Moreover, when the parasite 

 gets past the epithetal coverings of Englishmen the disease very often 

 takes on a chronic form and the sufferer may recover. Acute phthisis 

 usually supervenes in Polynesians and Red Indians, and they seldom 

 recover. 



