“The worm is about the thickness of a human hair, and is from three to four inches long. By two loops from the centre of its body it emits the Filariæ described by Carter in immense numbers. “My first specimen I got on December 21st, 1876, in a lymphatic abscess of the arm; this was dead. Four others I obtained alive from a hydrocele of the spermatic cord, having caught them in the eye of a peculiar trochar I use for tapping. These I kept alive for a day and separated them from each other with great difficulty. The worm when immersed in pure water stretches itself out and lies quite passive. In this condition it could be easily washed out of hydroceles through a large-sized trochar from patients known to suffer from Filariæ.” In July, 1877, I announced Bancroft’s discovery in the ‘Lancet,’ naming the parasite _Filaria Bancrofti_, and in the following September I sent the editor an account of the results of my study of the adult worms received from Brisbane in the interval. These examinations supplied me with the diagnosis already given (p. 181). On the 29th of September, 1877, Dr Lewis published a paper in the ‘Lancet,’ wherein, after alluding to my previous announcement respecting the discovery of _Filaria Bancrofti_, he describes under the name of _Filaria sanguinis hominis_ a mature worm, which was evidently the same parasite. Not unnaturally Dr Lewis put aside the nomenclature I had employed, on the ground that the name originally given by himself to the embryonal form ought to be retained, and that “a new name, if not necessary on anatomical grounds, would only lead to confusion.” Personally I have no objection to Lewis’s specific name, but if the question of priority is to determine the nomenclature, then I fear we ought to call the species _Filaria Salisburyii_. Obviously the retention of Dr Salisbury’s nomenclature (_Trichina cystica_) would be unsuitable and misleading. [Illustration: FIG. 39.--_Filaria Bancrofti._ _a_, Female (nat. size); _b_, head and neck (× 55 diam.); _c_, tail; _d_, free embryo (× 400 diam.); _e_, egg containing an embryo; _f_, egg, with mulberry cleavage of the yolk (× 360 diam.). Original.] When (prior to Lewis’s discovery of the hæmatozoa) I had myself encountered larval nematodes of the same character as those described by Salisbury, I, like Wucherer, was careful not to employ a special name for an immature form, which might or might not represent a worm hitherto known to science. The paper in which I described the adult worm from specimens supplied by Bancroft appeared in the ‘Lancet,’ Oct. 6th, 1877, the facts being stated as follows:--