368 PARASITES OF ANIMALS 



teric arterial disease of the ass. In relation to fatal colics in 

 the horse the study of verminous aneurism is of the highest 

 moment. On this subject Prof. Friedberger has published some 

 valuable lectures, in which, amongst other points, he incidentally 

 remarks upon the comparative freedom of military horses from 

 aneurism as compared with ordinary laboring horses. This 

 arises partly from the fact that the latter are not cared for to 

 the same extent, dietetically and otherwise; and, moreover, 

 cavalry horses are, as a rule, younger than ordinary working 

 animals. Whilst Friedberger, in his suggestive brochure, does 

 ample justice to the writings of his colleague, Dr Bollinger, it 

 may be said, in like manner, that he does not fail to recognise 

 his great indebtedness to the researches of Leuckart. So 

 practically important, however, do I deem Bellinger's summary 

 of the whole subject in relation to the hippopathological aspects 

 of parasitism, that I feel it desirable to record his conclusions 

 at full length. No professional man having any pretensions to 

 a knowledge of the veterinary art or, for that matter, to 

 parasitism in relation to sanitation should remain uninformed 

 on this subject. Dr Bollinger's results are thus stated : 



1. The worm aneurism of the visceral arteries of the horse, 

 existing in 90 to 94 per cent, of adult horses, has a general 

 correspondence with the aneurisma verum mixtum of man. It 

 is, however, distinguishable from the same by its seat, cause, 

 character of its walls, contents, and mode of termination. The 

 worm-aneurism arises from a parasitism of the palisade worm 

 (Strongylus armatus), owing to an inflammatory affection of the 

 arterial walls which it causes, and which one may describe as 

 a recurrent traumatic endo-arteritis. This holds good for all 

 the visceral arteries, with the exception of the abdominal aorta, 

 in which an aneurism may arise from local increase of pressure. 

 ' 2. The formation and further development of the aneurism is 

 also favored by the narrowing of the arterial calibre, which 

 is caused by the inflammatory swelling of its walls, and also by 

 the contemporaneous formation of a thrombus (clot), this latter 

 still further supporting and exciting the inflammation of the 

 inner coat. 



3. Whilst the causes above mentioned (and of these more 

 particularly the continued presence of the palisade worms and 

 the plugging of the smaller arteries by thrombi) favor the 

 growth of the worm-aneurism, the small size of the same, not- 

 withstanding the years it has existed, is explained by the con- 



