102 H. CHARLTON BASTIAN ON THE STRUCTURE AND 
It is not, however, universally distributed over the countries in which it is endemic, but 
is confined to certain limited areas, and is much more abundant at some times than at 
others—both which facts will be seen further on to have their special significance. 
In the regions where it is prevalent, this parasite is met with principally in the sub- 
cutaneous tissue of persons who have exposed themselves to certain conditions known 
to be favourable to the production of the disease*. In about four-fifths or more 
of the whole number ‘of recorded cases, these worms have been situated in the lower 
extremities, below the knees; and taking into consideration the fact that the people so 
affected mostly go about with bare legs and feet, and other evidence of a similar nature 
which will subsequently be alluded to, it is generally admitted at the present day that 
the worms are contained in some imperfectly known condition in the waters and damp 
plaees of these regions, and that they also in some unascertained manner make their 
way through the integuments of the body, and then acquire extraordinary dimensions in 
the subcutaneous or intermuscular cellular tissue. 
Having once located itself within the body, the worm grows rapidly, without producing 
any signs of irritation, or attracting much notice, for a period varying from eight to 
twelve or fourteen months. This has been aptly termed by Mr. Busk the “latent period” 
of its existence. After a time, however, the head begins to make its way to the surface, 
and then commences the long category of troubles peculiar to the disease, till the parasite 
has been completely extracted. 
` The worms are usually stated to vary in A from six inches to ten or twelve feet, 
and to be about $rds of a line in thickness. When fresh, they are of a milk-white colour, 
and nearly cylindrical. All that have hitherto been examined have been found to be 
undoubtedly female and viviparous, with the exception of three specimens, to which 
allusion will again be made further on. 
Having had six of these worms placed at my disposal for examination through the 
liberality and kindness of Professor Harley, of University College, I have availed myself 
of the opportunity of making a most careful investigation of their structure. But before 
stating the results of my own observations, I think it will be well to give a brief account 
of our previous knowledge on the subject. It is really surprising to find the ignorance 
which prevailed concerning the anatomy of this worm anterior to the writings of Busk 
and Carter, though this may be accounted for toa great extent by the comparative rarity 
with which these parasites are met with in Europe, and from many of the a 
having had but one, and that an imperfect specimen for examination. 
Rudolphi, in his earlier work t, has little to say concerning the anatomy of the Guinea- 
worm; indeed he confesses, *totius vermis anatome desideratur." The only positive 
characters he gives are, “ Margine oris tumido, caudæ acumine inflexo," whilst in his 
later work} he speaks of the numerous young contained within the parent worm in the 
following terms :—* Filariz nostree prole quasi farcte sunt, quod si harum longitudinem, 
illius vero minutiem spectas, foetuum multa millium millia singulis tribuit. Oviductuum 
* The Guineaworm has also been met with in dogs and horses. 
T Entozoorum historia naturalis, Amstelodami, 1809, vol. ii, pars 1. p. 55. 
. + Entozoorum Synopsis, Berolini, 1818, p. 205. 
* 
