150 THE PRINCIPLES OF HEREDITY 



nomadic life to live under a roof, even if it be in a warmer 

 region. 



247. "Here also an important part among the disease 

 factors is played without doubt by bad food, insufficient 

 clothing, and confinement in crowded, filthy, and badly- ven- 

 tilated huts ; and there is nothing to surprise us in the ex- 

 perience that consumption has increased to an alarming 

 extent among the Negroes of Arkansas of late, or since their 

 emancipation, the result being due, as the authority adds, to 

 the carelessness and shiftlessness of a class of people who 

 have been suddenly thrown upon their resources, and have 

 been withdrawn from the protection and consideration of a 

 race more intelligent than themselves." l 



248. The comparatively high mortality of Negroes from 

 phthisis demonstrates their extreme susceptibility. But 

 Professor Hirsch is mistaken in supposing that of all races 

 they are the most susceptible. In Cape Colony and else- 

 where they are able to multiply in contact with European 

 civilization. Under similar conditions the natives of the 

 Western Hemisphere perish from tuberculosis. Negroes are, 

 therefore, not nearly so susceptible to the disease as American, 

 Polynesian and Australian aborigines. 2 Natives of the 

 crowded city-settled peninsula of India, though less resistant 

 than the inhabitants of equally crowded but much colder 

 Europe, are more resistant than the Negroes, as the following 

 paragraph proves : 



249. " I pass now to another disease, phthisis, of which the 

 increase in this colony is undoubted, and so far progressive. 

 This increase has received notice more than once, and very 

 fully in a paper by Dr. Fergusson in the hospital reports. 

 I wish to direct attention especially to a phase of its local 

 development which is also noted by Dr. Fergusson the dif- 

 ferent clinical history which the disease presents as it occurs 

 in the two races forming the largest proportion of our very 

 mixed populations. Amongst the blacks the disease, con- 

 sidered from its clinical side, is generally of the rapid, acute 

 form known as 'galloping consumption,' or, looking at it from a 

 pathological point of view, it presents in that race the form of 

 tubercular caseous pneumonia. The phthisical East Indian, 

 on the other hand, presents the clinical characteristics of the 

 slower and more variable forms, or, speaking pathologically, 

 suffers most commonly from tubercular interstitial pneumonia 

 or peri-bronchitis. Now, why this difference ? We have as 



1 Hirsch, vol. iii., pp. 225-8. 

 2 See 306. 



