Oil GUINEA-WORM. 
505J 
a variety of pursuits has disengaged my attention from this ob- 
ject. The contrariety of opinions, however, that has at different 
times since then prevailed respecting the natural history of the 
dracunculus, and the pathology of the disease it produces, has, 
oflate, induced me to refer to my notes on this subject; and the 
results which I now beg to submit to the public through the 
medium of the Edinburgh and Surgical Journal, may not, per- 
haps, be found unworthy of their attention. 
A considerable portion of my practice in Grenada lay in the 
district called Point Saline ; and within the limits of this district 
did the dracunculus appear as an endemic and epidemic disease. 
“ This district, forming an isosceles triangle, the base of which 
may be four miles in length, is almost entirely composed of the 
soft rocky substance called tuf; and full a third of it is destitute 
of soil, except here and there in little hollows or fissures, or 
where the surface of tuf, softened by the action of air, has be- 
come a kind of vegetative earth. The whole of this immense 
mass is made up of laminae, inclining or horizontal, as the surface 
is acclivious or flat. Three conical hills, of about five or six 
hundred perpendicular feet in height, situated in the midst of this, 
constituting what is called Morne Rouge, are entirely composed 
of vitrified rocks and stones, of a black or brown colour, and 
scoriae intermixed with an earth exactly resembling iron rust re- 
duced to powder. No trace, however, of the crater of a volcano 
can be discovered on any of them ; but they are so placed with 
respect to each other as to form a very deep circumscribed hol- 
low, which seems to have been the crater of an immense volcano.” 
The tuf has been the produce of this volcano, and, similar to the 
same substance abounding in other volcanic countries, is a com- 
pound of ferruginated ashes and decayed lava — a circumstance of 
importance in an inquiry into the natural history of dracunculus. 
The whole of this district is destitute of natural springs, or run- 
ning streams of water of any description. In this district, thus 
singularly constituted, the negroes were necessarily restricted to 
the use of the water of wells dug in the tufy rock, near the inlets 
of the sea, and subject to the action of the tides. On some plan- 
tations, indeed, the owners had built tanks or cisterns, or had 
placed wooden reservoirs for the collection and preservation of 
rain water; and where these were sufficiently capacious, the 
field-negroes were permitted to use the water they contained in 
common with the white inhabitants and domestic negroes. But 
where such salutary accommodations had not been provided, ex- 
cept to the limited supply of the latter, the former invariably 
drunk the water of the wells. On the plantations thus cir- 
cumstanced, the guinea-worm was an endemic, and, during a 
