64 LECTURE VI. 



extremities, especially the feet, sometimes in the scrotum, and also, 

 but very rarely, beneath the Tunica conjunctiva of the eye. It ap- 

 pears to be endemic in the tropical regions of Asia and Africa. 



The length of this worm varies from six inches to two, eight, or 

 twelve feet; its thickness from half to two-thirds of aline; it is of a 

 whitish colour in general, but sometimes of a dark brown hue. The 

 body is round and sub-equal, a little attenuated towards the anterior 

 extremitv. In a recent specimen of small size, we have observed that 

 the orbicular mouth was surrounded by three slightly raised swellings, 

 which were continued a little way along the body and gradually lost ; 

 the body is traversed by two longitudinal lines corresponding to the 

 intervals of the two well-marked fasciculi of longitudinal muscular 

 fibres. The caudal extremity of the male is obtuse, and emits a 

 single spiculum ; in the female it is acute, and suddenly inflected. 



The Filaria medinensis, as has just been observed, is occasionally 

 located in the close vicinity of the organ of vision ; but another much 

 smaller species of the same genus of Nematoidea, infests the cavity 

 of the eye-ball itself. 



The Filaria oculi humani was detected by Nordmann in the Liquor 

 morgagni of the capsule of a crystalline lens of a man who had un- 

 dergone the operation of extraction for cataract under the hands of 

 the Baron von Grafe. In this instance the capsule of the lens had 

 been extracted entire, and upon a careful examination half an hour 

 after extraction there were observed in the fluid above mentioned two 

 minute and delicate FilaricB coiled up in the form of a ring. One of 

 these worms, when observed microscopically, presented a rupture in 

 the middle of its body, probably occasioned by the extracting needle, 

 from which rupture the intestinal canal was protruding ; the other 

 was entire, and measured three-fourths of a line in length ; it presented 

 a simple mouth without any apparent papillee, such as are observed 

 to characterise the large Filaria which infests the eye of the horse, 

 and through the transparent integument could be seen a straight 

 intestinal canal, surrounded by convolutions of the oviducts, and 

 terminating at an incurved anal extremity. 



The third species of Filaria enumerated among the Entozoa 

 hominis is the Filaria hronchialis ; it was described by Treutler* in 

 the enlarged bronchial glands of a man : the length of this worm is 

 about an inch ; it is slender, subattenuated anteriorly, and emitting 

 the male spiculum from an incurved obtuse anal extremity. 



The next human entozoon of the Nematoid order belongs to the 

 genus Tricocephalus, which, like Filaria, is characterised by an or- 



* Opusc, Pathol. Anat. p. 10. 



