ELEPHANTIASIS 87 



due to lymphatic obstruction, but in some cases even of 

 marked elephantiasis the obstruction is not due to filaria. 



As a very rare disease it may be seen in England, or in 

 other countries where Filaria bancrofti is unknown. In 

 the Tropics a similar chronic cedema may result from long 

 standing ulceration as is sometimes seen in the legs, or 

 from new growth as in many cases of granuloma pudendi, 

 or from repeated attacks of chronic erysipelas, and in 

 these cases the swelling may be very marked, as much so 

 as in a moderate case of elephantiasis. In these diseases 

 lymphatic obstruction is produced by inflammation or by 

 other disease, as in lymphodermia. Anything that could 

 cause lymphatic obstruction would lead to -similar result. 



In the Tropics elephantiasis is not a rare disease, but an 

 extremely common one, and an explanation is required 

 for the frequency with which this manifestation of lym- 

 phatic obstruction takes place there, and the frequent 

 existence of a worm in the lymphatics or lymphatic glands 

 affords a plausible explanation. The main arguments for 

 considering this to be due to nlariae are those based on 

 geographical, topographical and racial distribution of this 

 filariasis, as these to a considerable extent correspond with 

 the frequency of diseases due to lymphatic obstruction. 



In all countries where filariasis is common elephantiasis 

 is also common, and the variations in both are to some 

 extent proportionate. 



In the Pacific Islands and in the West Indies embryo 

 F. bancrofti (F. nocturna), or F. philippinensis are found in 

 20 to 30 per cent, of the population, and elephantiasis in 

 i to 2 per cent. 



In the Malay Peninsula, where filariae are not found in 

 the aboriginals, elephantiasis is unknown amongst them. 



In any country, the districts from which cases of 

 elephantiasis come are those in which filariae are frequently 

 found in the blood of the patients. 



Thus in Central Africa elephantiasis is common on the 

 Zambesi and Lower Shir rivers, and the north end of 

 Lake Nyassa, and in these districts filariae are found in 



