ANEURISM. 425 



ening of the arterial coats, without or with very slight dila- 

 tation, 8 small aneurisms from the size of a pea to a hazel 

 nut, 29 larger, varying from the size of a walnut to a hen's 

 egg, and 3 with hardening of the coats. The ages of the 

 animals varied from 6 to 20, chiefly from 6 to 11. Aneurism 

 is, therefore, not a rare, but a very common disease in the 

 horse, and in a number of cases of mesenteric aneurism 

 parasites are found occupying recesses in the thickened coats. 

 The parasite is a variety of strongylus Strongylus armatus 

 varietatis minoris which is often found in the textures of 

 solipedes. It is met with in the submucous tissue of the 

 ccecum, in the tunica vaginalis, peritoneum, &c. We know 

 nothing of the causes of this singular lesion, and are never 

 called to treat animals suffering from such a cause. 



ATHEROMA. 



Not unfrequently the arteries of the lower animals are 

 atheromatous. This condition is only interesting to us in a 

 pathological point of view, and Virchow very plainly states 

 in what the lesion consists. He says : 



" I have, in order to clear up to some extent difficulties, as they are 

 presented by an important, frequent, and at the same time much mis- 

 understood process, prepared a series of specimens exhibiting really 

 atheromatous conditions of the arteries. For it is particularly in the 

 case of these conditions that the confusion, which has prevailed with 

 regard to the interpretation of the change, has perhaps been the greatest. 



" At no period in the course of this century has a complete under- 

 standing ever been come to as to what was to be understood by the 

 expression atheromatous change in a vessel. Some have taken the term 

 in a wider, others in a narrower sense, but still it has perhaps been 

 taken in too wide a sense by all When, namely, the anatomists of the 

 last century applied the name of atheroma to a definite change in the 

 coats of the arteries, they of course had in their minds a condition simi- 

 lar to that of the skin, to which, ever since the days of ancient Greece, 

 the name of atheroma, grit-follicle, (Griitzbalg) [sebaceous or epidermic 



