308 Proceedings of Royal Society of Edinburgh. [sess. 
body in which it makes its appearance, in at least 95 per cent, of the 
cases, it is met with in the lower extremities. In a person suffering 
from Guinea-worm the first symptom usually noticed is a cord-like sub- 
stance felt beneath the skin. There is usually some pain, and more 
or less fever, the temperature of the patient being sometimes exceed- 
ingly high. As the worm commences to make its exit from the 
body, a small blister forms at the point it selects for its escape ; 
this blister is often surrounded by a distinct rash. 
XV. Filaria Sanguinis Hominis. 
(See Plate XI.) 
Definition . — The Filaria sanguinis hominis is a nematoid 
hsematozoon, about the thickness of a hair, and from 3 to 4 inches 
in length, which is found in the blood of some animals and men. 
Its geographical distribution is of importance, because when the 
parasites gain entrance into a human being, in the tropics at any 
rate, they frequently induce chyluria, lymphorrhagia, elephantiasis, 
lymphangiechodes, chylous hydrocele and varicocele, and possibly 
also true elephantiasis arabum. It may be incidentally remarked, 
that the filaria are almost invariably totally absent from the blood 
during the day — i.e ., from 9 a.m. to 6 p.m. They commence to appear 
between 6 or 7 in the evening, rapidly increase in number until their 
maximum.is reached about 2 or 3 a.m., and then gradually disappear. 
Geographical Distribution . — As far as we are yet aware, the 
Filaria sanguinis hominis occurs principally, if not entirely, in 
tropical regions. It is known to be indigenous in the follow- 
ing regions, but it is not improbable that future observations 
will show its distribution to be rather greater than that which we 
can now give to it. Commencing with Brazil, it is most extensively 
distributed throughout the tropical parts of that country, excepting 
however the southern districts and the province of Sta-Caterina. In 
all probability, too, it occurs in Chili, Peru, Venezuela, and Mexico, as 
also in Guiana. It certainly occurs in Barbadoes, Cuba, Mauritius, 
St Domingo, and St Thomas. In Africa it is found in Egypt, on 
the shores of the Zambezi and Lake Nyassa, the Zanzibar coast, 
Mauritius, and Reunion ; it is probably indigenous on the west coast, 
and it has been met with in various districts of the Negro part 
