84 INFECTIOUS AND PARASITIC DISEASES. 



control of tropical diseases are studied, and where the 

 same is taught to physicians and nurses whose duty 

 it may be, at some time, to cope with them. 



An ever present danger to both natives and foreigners 

 in tropical countries is intestinal diseases. The climatic 

 conditions predispose to congestion of the abdominal 

 viscera, which predisposes the latter to infections. 

 Even in the absence of infectious agents, chronic 

 engorgement may give rise to lasting injury in one or 

 another organ. The liver is the organ commonly 

 affected in this way, a chronic enlargement with result- 

 ing torpidity in functioning, frequently making the 

 unfortunate sufferer an invalid for life. Lay writers, 

 particularly English authors, have long recognized this 

 affliction, and very properly held it responsible for 

 many disagreeable traits of character. The enlarged 

 liver of the retired East Indian official so often referred 

 to by Thackeray, is therefore not a mere creation of 

 the novelist's, but founded upon fact. But the chief 

 interest for us in the congestion of the viscera due to 

 intense heat, is in the fact that it predisposes to a host 

 of infectious and animal intestinal parasites with which 

 the tropics abound. Nearly all of these agents get into 

 the body through the drinking-water, or from eating 

 raw fruits and vegetables, and the infectious disorders 

 which they excite are either of the intestines, or the 

 intestines and liver. The commonest infectious disease 

 of the tropics is dysentery, of which there are two 



