condition as regards exposure to light and sun, the metamorphosis of the guinea-worm inside the cyclops would have been completed. This shows that it would be possible to introduce the guinea-worm into England if we did not wear boots or shoes, and if we were in the habit of wading about in pools and marshes as do the natives of West Africa. There would be a discharge of the embryos into the water, and if less care were taken about the purity of the water-supply, and supposing there to be no adverse climatic influences, the worm would become common. This little story about guinea-worms shows how these and similar parasites pass from one man to another; and it shows how slight differences of habit, absence of intermediate host, and so on, govern the distribution of a parasite like _Filaria loa_. If you examine this _Filaria loa_ exhibited by the President under the microscope, you will see that all over the skin there are minute but regular bosses or protuberances. This occurs in certain filariæ, but in no other human species so far as I am aware. These protuberances, I have no doubt, have a bearing on the locomotive habits of this particular parasite. I pass round a reproduction by Blanchard from a book which carries us back a century further in the history of the _Filaria loa_ than that given by Dr. Robertson. This book was written by Pigafetta,[8] and it contains a picture showing a man drawing a guinea-worm out of his leg, and a woman having a worm removed from the eye, doubtless a _Filaria loa_. FOOTNOTES [1] Bajon’s ‘Mémoire pour servir à l’histoire de Cayenne et de la Guyane,’ t. 1er, p. 325, 1777. [2] Arrachart, ‘Mémoires, dissertations de Chirurgie, et observations de Chirurgie,’ 1805, p. 228. [3] ‘Lancet,’ vol. i, 1844, p. 309. [4] Ibid., Nov. 26th, 1859. [5] ‘Zoologie médicale,’ 1859, vol. ii, p. 143. [6] ‘Annales d’Oculistique,’ 1864, p. 241. [7] ‘American Journal of the Med. Sciences,’ 1877, vol. lxxiv, p. 113. [8] ‘Vera descriptio regni africani, quod tam ab incolis quam Lusitanis Congus appellatur,’ Frankfort, 1598. [Illustration: PLATE VII Illustrates Dr. Argyll Robertson’s paper on Filaria loa. FEMALE FILARIA LOA. FIG. 1.—The whole worm. Portions of alimentary canal and uterine tube protruding through an opening in the wall of the parasite. FIG. 2.—A portion of uterine tube, highly magnified, showing embryo filariæ in interior. FIG. 3.—Head of worm, with rounded projection of wall of worm at one point, due to injury. FIG. 4.—Part of worm where rupture of wall occurred. _a._ Alimentary canal. _b._ Uterine tube with embryo filariæ.] FURTHER NOTE OF CASE OF FILARIA LOA. _Read at the Meeting of the Ophthalmological Society on March 14th, 1895._ By D. ARGYLL ROBERTSON. (With Plate VII.)