STRONG-YLU8 ARMATUS. 
367 
certain, is that the concealed testicles of horses affected with 
abdominal cryptorchidism often exhibit such alterations as 
fibrous tumors or serous cysts. 
In stallions affected with hydrocele, Schmidt and Pottinger 
have remarked one or two specimens of this worm in the vag¬ 
inal sheath. Their presence is easily explained by the com¬ 
munication that exists between the abdominal cavity and that 
sheath. 
Pathological Anatomy .—The verminous aneurism is usually 
fusiform, sometimes globular or cylindroid. Its average size 
is about that of a walnut, though it may not exceed that of a 
pea, or it may attain the dimensions of a man’s head. 
It consists of a dilation of the affected artery, with hyper¬ 
trophy of its walls. The dilation is sometimes absent, not¬ 
withstanding grave thrombic lesions in the vessel. (Durieux.) 
The external tunic is usually thickened, and variably- in¬ 
durated, according to the age of the tumor. It adheres firmly 
to the neighboring parts, and is more or less confounded with 
the connective tissue. 
The middle tunic is always hypertrophied, and sometimes 
very much so. Its thickness—which is ordinarily about a 
millimetre—may attain, and even exceed, two centimetres. 
At one time this thickening is due to simple hypertrophy of 
the tunic; at another time it is owing to inflammatory phe¬ 
nomena, with atrophy of the muscular fibres. 
The internal tunic is nearly always altered. It may present 
every degree of endarteritis, and of regressive metamorpho¬ 
sis—from partial thickenings, and a white, milky tint, to ulcera¬ 
tion, atheromatous transformation and calcification ; the latter, 
however, is always rare, and may exceptionally assume an as¬ 
pect of real ossification. 
In the interior of the aneurism there is usually a fibrinous 
deposit—a thrombus—always adhering, though to a variable 
degree, to the internal membrane. It is more or less regular 
and consistent, and partially blocks the vessels; but there is 
always a canal in the middle of the passage of blood. This 
thrombus is often prolonged in the artery beyond the aneurism, 
both before and behind ; and its external layers are capable of 
