78 THE INTERNAL PAEASITES OP 



hagen Veterinary School), referring to this entozoa, says, 

 " In the condition of thin-shelled eggs and free embryos, 

 they either lie in the windpipe or they occupy the cavities 

 of the finest bronchial tubes ; and in these situations they 

 not unfrequently set up inflammatory action, with more 

 ■or less obliteration, thus rendering the lungs impervious." 

 (Husdyreneslnvoldsorme, Tidsshrift forVeterinairer, 1872.) 

 In a similar way, the adult forms of Strongylus filaria 

 occupy the bronchi, chiefly those of medium size; and 

 here, as remarked by Leuckart, they either produce a 

 simple catarrh, or set up an inflammation which ' ' diffuses 

 itself over a great part of the lung, ultimately causing 

 death." 



The question which agriculturists should be chiefly 

 desirous of solving is that appertaining to the mode of 

 origination and development of these parasites ; for, by 

 acquiring accurate data on this head, it is not altogether 

 unreasonable to suppose that we may hit upon a more or 

 less perfectmethod of limiting or eradicating the disastrous 

 epizootic associated with an excessive multiplication of 

 these creatures during particular seasons. In the present 

 nascent and imperfect state of our knowledge respecting 

 the phenomena in question, I purposely forbear to utter 

 all that I might advance respecting their prophylactic 

 bearings ; yet I trust that the various agricultural socie- 

 ties will appreciate the importance of the foregoing 

 data in relation to the practical interests they have 

 justly so much at heart. One society, indeed, has 

 involved me in a lengthened correspondence on this 



subject. 



As regards certain other nematode parasites, it is only 

 necessary to state that the sheep is infested by at least 

 six more species, making in all eight ovine nematodes. 



