CHAPTER V 



TROPICAL DISEASES 



Preliminary remarks — Evolution — Geographical discovery — Endemicity — 

 Epidemicity — Eugenics — Incidence — Distribution- — Prevention- — Refer- 

 ences. 



PRELIMINARY REMARKS. 



Before entering upon the systematic study of tropical diseases a 

 few remarks may be made upon their evolution, the influences of 

 geographical discovery upon their dissemination, their endemicity 

 and epidemicity, tropical eugenics, the geography of tropical disease 

 with special reference to countries and not to given diseases, and 

 finally the prevention of these diseases. 



It will be obvious that, if these subjects were to be treated at all 

 fully, they would require several volumes, each of which would be 

 larger than the present little book; but this is not our object, which 

 is to bring subjects to the notice of the tropical practitioner with the 

 view that he may apply them to the diseases and peoples by whom 

 he is surrounded, and references are given whereby he may extend 

 his reading and knowledge far beyond the confined limits of our 

 manual. 



All tropical countries are inhabited by three different sets of 

 inhabitants. Firstly, there are the true indigenous natives ; secondly, 

 there are immigrants from other countries; and, thirdly, there are 

 the descendants of an admixture of the first two, and generally of a 

 European with a native. Such are the Mulattoes of Central and 

 Southern America, the Eurasians or Anglo-Indians of India, and the 

 Burghers of Ceylon, and it is our duty to 1 ry to trace out the cause 

 of disease and death among these peoples, 



EVOLUTION. 



Auckland Geddes and Adami consider that the Piltdown skull is 

 pathological, and that its remarkable thickness and the bold out- 

 line of the temporal ridges are to be explained by the assumption 

 that its original owner suffered from acromegaly. 



The researches ot the late highly talented Sir Armand RufEer into palcso- 

 pathology have demonstrated the existence of bilharziosis, tuberculosis, rheu- 

 matoid arthritis, and pyorrhoea alveolaris in Egyptian mummies dating some 

 4,000-6,000 B.C., while certainly some of the organisms of disease were present 

 then, as he was able to demonstrate the tubercle bacillus in mummies of the 

 Twelfth Dynasty. 



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