The first discovery of this entozoon, in its embryo state, was made by Wucherer on the 4th of August, 1866. To use Dr Da Silva Lima’s words:--“At the moment when Wucherer was seeking for the _Bilharzia hæmatobia_, he found instead of it an unknown worm. Our illustrious collaborator,” adds Dr Lima, “has made his important discovery known under the modest title of ‘Preliminary Notice on a species of Worm at present not described;’ and still more modestly Wucherer formulated in the following manner his judicious and prudent conclusions:--It would be rash on my part to put forth a conjecture on the coexistence of these worms of the hæmatochyluria, and on the etiological signification which they might have. I shall therefore abstain until I have been able to make more ample investigations, and until I have been permitted to examine the corpse of a hæmaturic, which has not yet been possible.” (‘Gazeta Medica da Bahia,’ Dec., 1868, p. 99.) In the year 1868 Dr J. H. Salisbury referred certain ova which he found in the urine to a new and distinct species of nematode. Although he had no acquaintance with the adult parasite, Dr Salisbury at once placed the “species” in the genus Trichina. Here is what he says:--“_Trichina cystica_ (Salisbury).--This is a small species which I have found in the human bladder. In all my examinations I have met with this little entozoon in three cases only. In two of these it was only occasionally met with in the urine. In the other it occurred in great numbers. Frequently from ten to fifteen ova were found in a single drop of urine.” It is important to remark, that there was no hæmaturia in the last-named case, which Dr Salisbury describes as one of “cystinic rheumatism,” or “severe cystinæmia associated with rheumatism and paralysis.” The patient “had been insane for several years. Her urine was passed milky, with granular cystine, and was dense and scanty.” It is likewise added: “No examination was made of the muscles after death to determine whether this species burrowed in the tissue, like the (_Trichina_) _spiralis_.” So much for the principal facts recorded by Dr Salisbury. His paper is accompanied by two woodcut figures of the ova (× 300 diam.), and one representation of the embryo (× 1000 diam.). If these figures give the size correctly, the ova measure only about 1/800″ in length, by 1/1560″ in breadth, whilst the embryo would be about 1/500″ from head to tail.