Account of a Filaria in a Horse's Eye. 28 1 



These cysts appear, when examined with a lens, not exactly 

 ovoid, but irregularly contracted towards one extremity, so as to 

 form a kind of short neck. These are dispersed throughout the 

 the muscles over the body, and are placed in the direction of the 

 fibres, in the cellular membrane, immediately investing the mus- 

 cular fibrillsg, or the tendinous fibres to which they are attached. 

 In a recent specimen, one and sometimes two thread-like worms 

 may be seen, coiled up in each cyst. Mr. Owen regards this an- 

 imal as closely allied to the eels which are found in paste and 

 vinegar, and has given it the name of Trichina spiralis. It is 

 very probable that some anomalous diseases may be occasioned 

 by the great multiphcation of these worms, while the cause is 

 unsuspected and inexplicable. 



The most common worm met with in the different classes of 

 animals, is the fluke, or Fasciola hepatica, which is sometimes 

 also found in man. We find it in cattle, sheep, swine, and deer ; 

 in reptiles, fishes, and even worms of the largest kind ; and it is 

 this which occasions the disease called the rot in sheep. Leuwen- 

 hoeck counted 870 of these animals in one liver. Hydatids are 

 also found in sheep, in the brain and liver, and often carry off 

 whole flocks. This is also met with in man, swine, deer and 

 oxen, of which there are three different species, viz. cerebralis, 

 vervecijia, and ovilla. It is unnecessary however to go into de- 

 tail, in relation to the different species of parasites which inhabit 

 the different races of animals ; it must suffice to state, that they 

 are extremely numerous, — that though some are common to sev- 

 eral species, yet that, in general, each has its peculiar parasite ; — 

 and, moreover, that probably each texture and organ furnishes a 

 habitation for a distinct race of inhabitants. To this it might be 

 added, that many of these parasites have parasites of their own, 

 so that they are literally paid in their own coin. 



It has been remarked that the Filaria belongs to the order Ne- 

 matoidea of Rudolphi. This order embraces those animals whose 

 external skin is more or less furnished with muscular fibres, and 

 usually striated transversely; containing an abdominal cavity, in 

 which is a distinct intestinal canal, extending nearly the whole 

 length of the body. The intestine is connected with the neigh- 

 boring parts and the general envelope of the body by numerous 

 threads, considered by some writers as vessels for the conveyance 

 of the nutritious fluid, and by others as trachece, but without suf- 



