SNAKES AND BLOODSUCKERS 



to West Africa, and in the course of twenty-five years it has spread 

 over the whole continent, reaching even the East Coast; and on 

 Lake Victoria Nyanza whole villages were depopulated by this 

 horrible pest, for which the natives could find no remedy. The 

 insect lives in the dust of houses and streets. Once its presence has 

 become perceptible, it is best — or so I was assured in north-eastern 

 Brazil — to get a negro to extract it. The negroes use the long knife 

 which they always carry, employing it as a 

 weapon, a table-knife, and a toothpick, and with 

 the greatest dexterity they cut the insect out of 

 the toe. 



Travelling through Pernambuco, and also in 

 other parts of the interior of Brazil, one often sees 

 people standing about the railway-stations whose 

 bloodless faces, jaded bearing and fatigued ex- 

 pression are at once conspicuous. These people 

 are suffering from a malady very common in 

 Brazil, and which, after syphiHs, is doing more 

 than any other to undermine the health of the 

 nation. The extirpation of these two diseases is 

 the most important, but also, perhaps, the most 

 difficult problem before the country, and one 

 that must be solved if its future is to be 

 prosperous. 



This disease, which in Brazil is almost a 

 national pestilence, is caused by an intestinal 

 parasite, the hookworm. It is about two-fifths of 

 an inch in length, and it anchors itself, with its 

 formidable teeth, to the mucous membrane of 

 the small intestine (Fig. 40). This worm abso- 

 lutely eats its way into the wall of the intestine, 

 which, being wounded by its teeth, begins to 

 bleed, and it is to this constant loss of blood that the pallid 

 complexion of the sufferers is due. It seems, however, that certain 

 toxic symptoms of the disease are caused by the juices which the 

 worm injects into the wound. 



The eggs produced by the female hookworm reach the outer 

 world in the dejecta, and develop in the moist soil. From the soil 

 the tiny larvae (Fig. 40) may find their way back into the mouth; 

 and this is especially possible in the case of persons whose work 

 brings them into contact with the soil, as, for example, the men 



z 353 



Fig. 40. — Head of 

 Hookworm from 

 human intestine. 

 T, teeth, 0, oeso- 

 phagus ; g, glands. 

 Beneath, the lar- 

 val state, showing 

 gut and el ngated 

 sacs, the rudi- 

 ments of the 

 generative organs 



