MALARIA EXPEDITION TO NIGERIA 53 
of Abyssinia, the disease is met with. In the upper valley of the Nile (Nubia and 
the neighbouring countries of the negro) elephantiasis would seem to be unknown ; 
on the other hand there are accounts of its endemic occurrence at some places in the 
Greater Soudan, such as Bornou, Segu Sicorro, and Ogooue. Under the same 
circumstances of locality we rind the disease widely endemic in the Western 
Hemisphere : as in the coast regions of New Granada, Venezuela, and Peru ; in 
those parts of Brazil that are mostly tropical in character. On the coast and marshy 
levels of Guiana ; in many islands of the West Indies such as the Barbadoes, 
Martinique, Guadaloupe, Trinidad, St. Vincent, and St. Bartholomew ; as well as on 
the Gulf Coast of the Central American States of Nicaragua, Costa Rica and Panama 
and of Mexico. 
In Europe, in Greece it is very rarely met with ; it has been more frequently 
seen in Turkey; in the south of France also, and in Lisbon and southern Spain 
it would appear to be relatively common ; but the patients may be in great part such 
as have acquired elephantiasis in the East.' 
As to the demonstration of the presence of F. nocturna in the inhabitants of 
these countries, search for the adults and the microscopical examination of the blood 
for embryos has not yet been very extensive ; but in so far as observations go, the 
results roughly cover the same extensive distribution as that of elephantiasis. 
Manson 1 has examined blood films from many parts of the world, including Old 
Calabar, the Lower Niger, Dahomey, Zanzibar, Mombasa, in Africa ; Madras, Cochin, 
Ceylon in Asia ; Samoa, Fiji, the Friendly Islands in Polynesia ; Georgetown, 
New Amsterdam, and the littoral of Demarara in British Guiana ; and the islands 
St. Vincent, St. Kitts and Montserrat, and Trinidad among the Islands of the West 
Indies. 
Filaria diurna. As the presence of this blood parasite is not associated with any 
marked pathological lesion, the determination of its geographical distribution (necessitating 
the microscopical demonstration of the embryos in the blood, and of their characteristic 
diurnal periodicity), has not been so exactly nor so extensively made. In 1900, 
Manson 2 states that he has twice encountered the embryos of F. diurna, once in a 
negro from Old Calabar, and another from the Congo ; and further, that from recent 
observations, he believes it to be very common (one in four) in certain districts on 
the lower Niger. This short account seems to be the whole of the present knowledge 
of the distribution of the F. diurna throughout the whole world, excepting the 
discovery of what, we think, must be taken as F. diurna in the Friendly Islands by 
Thorpe 3 ; this will be referred to again later. 
Filaria perstans. For similar reasons as in the case of F. diurna — the absence 
of apparent pathological lesions and of the necessity of frequent daily microscopical 
1. Manson, Tropica/ Diseases, London, 1900, p. +83. 
2. Manson, Tropical Diseases, London, 1900, p. 532. 
3. Thorpe, British Medical Journal, 1896, vol. ii, p. 922. 
