Distribution of Tropical Diseases in Africa. 481 
Johns-Hopkins Hospital Reports), yet both diseases may to 
a certain extent be combined, and the precautions necessary 
to avoid the one are those which would prevent the other. 
Both diseases are most prevalent in the hot and rainy 
seasons; both are liable to be produced by rapid alternations 
of temperature and by chill. Therefore persons in Tropical 
Africa should avoid chill by means of careful clothing, and 
by the invariable use of a cholera belt. Excessive exertion 
also predisposes to both diseases, and both are especially met 
with in damp, swampy places, and in all districts where the 
soil is impregnated with decaying vegetable débris. The 
drinking water should be as pure as possible, and in cases 
where the water-supply is doubtful, it should be filtered 
and boiled. All stagnant water should be, if possible, 
avoided. It is also of importance to remember that both a 
monotonous diet and salt rations frequently induce diarrhea, 
and predispose to dysentery. Unripe fruit, and especially 
over-ripe fruit, should be avoided. There is no doubt that in 
Africa many cases of diarrhoea and dysentery are induced by 
exposure to the night air, and also by sleeping on the ground. 
Where they are prevalent, it is well to isolate the patients, 
and to carefully disinfect their excreta; and finally, it must 
be borne in mind that malaria may complicate both diseases, 
and that then, unless the malarious factor is taken into 
account, the disease cannot be cured. 
One may summarise the predisposing causes of dysentery 
and diarrhcea as follows:—Frequent exposure to malaria, 
great bodily fatigue or excessive anxiety and mental distress, 
excess in the use of alcohol and tobacco and narcotics, over- 
crowding, the use of tainted food or the prolonged employment 
of salt provisions, and lastly, the too frequent employment of 
strong purgative medicines. The exciting causes of these 
diseases are—unwholesome drinking water, the use of 
indifferent food, great and sudden vicissitudes of temperature 
and chill, impure air, intestinal worms, and abscess of the 
liver. 
Nothing need be said as to the treatment of diarrhcea, as 
this must be carried out on general principles; but with 
regard to dysentery, my experience points to the advisability 
