78 TROPICAL MEDICINE AND HYGIENE 



believed to be the cause of intestinal diseases, and par- 

 ticularly of a form of diarrhoea known as Cochin China 

 diarrhoea. It is now known that they may be present in 

 numbers in persons in perfect health, and passing normal 

 motions. In such persons, if diarrhoea be artificially 

 induced, as by purgatives, the numbers of embryos passed 

 will be much increased. 



They are more frequently found in persons with diar- 

 rhoea, and although they cannot be considered as the 

 cause of the disease, apparently abnormal intestinal con- 

 ditions are favourable to their multiplication, or that 

 they render the intestine more liable to catarrhal or 

 other conditions, and so indirectly lead to intestinal 

 trouble. 



Strongyloides intestinalis is a common human parasite, 

 and widely distributed all through the Tropics. The 

 larvae are small, but can be readily found on microscopic 

 examination of the excreta, whether these are loose or 

 formed. As a direct cause of disease, it is probably 

 unimportant. 



