226 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [III, III.

followed by it, can really take place, since a single larva in the subcutaneous situa-
tion has been seen to produce quite large areas of degenerative foci, probably due
in part to the burrowing nature of the exudative fluid. In a number of these large
degenerative areas, one can make out only a few interlacing strands of adult con-
nective tissue and an occasional capillary in an otherwise homogeneously
eosinophile mass. In places, organisation is seen to have taken place, either whole
or in part; in others, it has scarcely started. Any parasitic debris which is not
removed by phagocytosis, is soon made innocuous by the deposition of lime salts.
Lesions in the prepuce show a very marked predisposition to calcification and to
extension, but these features have been seen occasionally in the lesions in other
situations.

The most outstanding and fundamental changes, however, concern the blood
capillaries. When the degenerative changes in the endothelium of the capillary
have not gone very far, a thin layer of a delicate endothelium can be recognised
without much difficulty (Plate XVIII, fig. 2). Certain vessels show varying degrees
of endarteritis with partial or total obliteration of the lumen by the replacing
connective tissue and also an increase in the amount of elastic tissue at places.
The commencing inflammatory changes in the vessel wall are represented by a
tendency to diffuse staining (Plate XV, fig. 2). More severe inflammations are
manifested by a marked dilatation of the wall due to infiltration with exudative
cells. The degree of exudation apparently determines whether only the endothe-
lium is to be proliferated or shed, or the vessel wall is to undergo necrosis, calcifi-
cation or total disruption. The desquammated endothelial cells can be seen lying
scattered in the periphery of the thrombus mass formed in an affected vessel, or
where the wall has given way, the endothelial cells may be wandering free in the
matrix of the growth.

It is important to note here that apparently healthy worms in cross — or lon-
gitudinal sections have been seen lying quite free in the more or less dilated lumen
of capillary vessels (Plate XIX, fig. 1) with varying degrees of degenerative change
in the vessel wall (Plate XV, fig. 2). On measurement, larvæ are seen to vary in
size within certain limits and from this, one presumes them to be in slightly
different stages of development. Usually the larvæ are seen lying straight and
singly but occasionally a single worm in a coiled form (Plate XV, fig. 1) or several
worms may be encountered in a larger sized capillary. A central intestinal canal
and a number of cuticular ridges at regular intervals can be seen in cross-sections,
(Plate XV, fig. 2) or if the parasite has been cut longitudinally, the characteristic
striations, both longitudinal and transverse (Plate XVIII, fig. 1), can be made out
in the worm structure inside the vessel. Expert helminthological opinion was