PARASITES OF MAN. 327 



of entozoa frequently occur in sufficiently prodigious numbers to sweep 

 off tlieir victims by hundreds or even by thousands. Animal epizootics 

 due to this source have hitherto been little studied. 



Nematoda contixued. 

 3i.—Existrongijlus gigas, Diesing. 



Synonymy. — Strongyhts gigas, Kudolphi ; Ascaris renalis, Gmelin ; 

 Lumbricus in renibits, Blasius ; Fusaria, Zeder. 



Larvffi. — The embryos are vermiform, and measure about the jJ^ 

 of an inch in length. In their higher larval state they have 

 been recognised as filarise (F. cystica.) 



Intermediate Host. — From the anatomical observations of 

 Schneider and Leuckart, it would seem that the immature 

 worms dwell chiefly in freshwater fishes. Thus, the so-called 

 Filaria cystica must be regarded as an immature Eustrongylus 

 gigas. Hitherto, this little worm has been found occupying cysts 

 or capsules, situated immediately beneath the peritoneal mem- 

 brane in Galaxias scriha, and in certain oceanic fishes belonging 

 to the genus Synbranchiis. According to the eminent piscico- 

 logist, Miiller, the GalaxiidiP present strong affinities to the 

 Salmonida, but Cuvier considered them as essentially modified 

 pikes (Esocidie.) 



Experiments. — Balbiani attempted to rear Eustrongyli by direct 

 experiment. He administered the ova to dogs, but obtained 

 only negative results. Similarly, his experiments on reptiles 

 and fishes failed. 



Remarks. — If the conclusions of Schneider and Leuckart be 

 correct — and these make it appear that we must hold certain 

 freshwater fishes as responsible media of infection — one can 

 only express surprise that man is so seldom ■victimised by this 

 parasite. The Synhranchi, being tropical fishes, can have little 

 part in the infection of animals — apai-t frora seals. One must 

 suppose that pumas, dogs, wolves, gluttons, raccoons, minks, 

 weasels, and other carnivora contract this worm by attacking, 

 capturing, and devouring fishes at times when they are 

 prevented from obtaining other and more readily accessible 

 kinds of food. How this parasite should in some instances 

 gain access to herbivorous animals is not so clear. 



Lit. — All standard works, and especially Leuckart's. One of the 

 most remarkable memoirs quoted by Davaiue is that of 

 Glamorgan. In this old writer's work, "La Chasse de Loup," 

 dated 1583, the kidney-worms, or Eustrongjii of modern writex's, 

 are characterised as " sei-peuts and higlily venomous beasts." 

 35. — Strongylus broiichialis, Cobbold. 



Syn. — Strongylus longevaginatus, Diesing; Filaria bronchialis, 

 Rudolphi ; Hamularia, Treutler. 



Larvae. — Unknown. 



Kemarks. — This small viviparous eutozoon, hitherto only twice 

 encountered in the human body, is doubtless identical with 

 Strongylus longevaginatus. The original specimen was discovered 

 by Treutler in Germany, in 1791 ; the second being found by 

 Dr. Jortsits, in Transylvania, many years afterwards (1845.) 

 The males measure half an inch and the females rather more 

 than an inch in length. 

 36. — Dochmius duodeiialis, Leuckart. 



Syn. — Dochmius anchylostomum, Molin ; Anchylostoma duodenale 

 Dubini ; Strongylus quadridentatus, Von. Siebold ; Sclerostomy 

 Cobbold. 



