Knowing what errors of interpretation have often crept into helminthological literature I was more than usually cautious in pronouncing upon the source of these urinary parasites. Accordingly, I remarked that “future discoveries might enable us to identify the species of nematode to which these ova are referable.” I also added:--“Notwithstanding discrepancies as to size, I am inclined to think that Dr Salisbury and myself have been made acquainted with nematode eggs and embryos referable to one and the same species of parasite. I do not care to speculate as to the origin of these ova. Long ago I gave in my adhesion to the determinations of Schneider in respect of the so-called _Spiroptera hominis_, but I am by no means certain that his position may not be disturbed by fresh discoveries. It is not a little remarkable that the parents of my patient should have averred that she passed three small vermiform entozoa by the urethra, corresponding, to judge from their verbal statements, very closely with the ordinary appearances of _Filaria piscium_.” Having written thus much seven years back, it is with natural pleasure that I find my anticipations already verified. Knowing that I was dealing with parasites in their earliest larval stages, it never occurred to me to give a specific name to them, and I could not possibly approve of Dr Salisbury’s nomenclature, for which there was no good ground. In the original discovery Dr O. Wucherer procured the worms from the chylous urine of a female in the Misericordia Hospital at Bahia; and on the 9th of the following October, 1866, he obtained similar worms from another female suffering from hæmaturia. He also afterwards found them in a man whose urine was slightly chylous, but not hæmatic. In all cases these sexually-immature nematodes were alive. In September, 1872, Dr A. Corre furnished a careful description of similar worms found by Dr Crévaux in a hæmato-chylurous patient at Guadeloupe. Dr Crévaux frequently examined the blood of this patient but found no hæmatozoa. In like manner in Brazil, Dr J. Silva Lima sought in vain for worms in the blood of no less than five patients, all of whom suffered from hæmaturia, and whose urine contained numerous nematoid worms.