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101
which had persisted for two years, were at an advanced stage and earlier chang-
es could be seen in the peripheral region. At the centre there was granula-
tion tissue (Plate VI, fig. 2) and in its centre the parasitized endothelial cells
were few and not readily detectable, while the parasites stained feebly and
were ill-defined. A greater part of this region revealed a sero-fibrinous type
of inflamation resulting in dilatation of the lymphatic channels (Plate VII,
fig. 1) and the formation of loose cellular matrix due to diapedesis of lympha-
tic and other inflammatory cells in that region. Columns of endothelial cells
or the macrophages in this region were found disposed in the vicinity of the
dilated lymphatics and contained leishmania bodies in their cytoplasm.
The process of cellular degeneration at certain places in this region resulted
in the formation of structureless masses containing only occasional cells
(Plate VII, fig. 2) including parasitized macrophages.
Histological examination of the superficial part of the sore in the central
region revealed the solution of continuity of the epidermis (Plate VII, fig. 3),
whilst the peripheral region was characterised by an intense cellular infiltra-
tion and the congestion of blood vessels in the papillary portions of the corium.
The most important finding in this region is the presence of numerous nest
cells regarded by Lazarus-barlow as characteristic of this condition (Plate VII,
fig 4). The rete malpighi layer is hypertrophied, grows downward and branch-
es into the underlying corium. The cells of this layer show marked peri-
nuclear vacuolation. The papillary region shows excessive proliferation
and hypertrophy leading to encroachment on and disintegration of the rete
malpighi which as a consequence becomes transformed, to a certain extent,
into isolated masses of cells (Plate VII, fig. 3) lying in the corium. The papil-
lary part of the corium shows an extensive invasion by macrophages (Plate
VIII, fig. 1) containing numerous leishmania parasites. In the corium proper
and in the vicinity of sebaceous and sweat glands accumulations of macro-
phages are found near blood vessels some of which were occluded with pro-
liferated endothelial cells. Careful examination of the dilated blood vessels
in this region revealed a few intimal cells (Plate VIII, fig. 2) containing the
causative micro-organisms. Proliferated intimal cells occluding the lumen
of the smaller blood vessels (Plate IX, fig. 1) have also been observed con-
taining the parasites, and the macrophages considered as typical of leishmania
infection may thus be regarded as proliferated endothelial cells. The parasites,
besides occurring intra-cellularly, have also been observed lying free in the
lumen of a lymph vessel (Plate IX, fig. 2) and in tissue spaces mixed with in-
flammatory cells.
Our observations on the histopathology of this disease in the bovine host
agree closely with the published accounts of leishmaniasis in man by Manson
[1907], Wright [1903], Brooke [1903] and Balfour [1917] and that in canines
by Mill, MacHattie and Chadwick [1930]. Contrary to the observations
of Jeanselme and Rist [quoted by Balfour, 1917] on the histopathology of
' Bouton d'orient' focal necrosis and giant cells formation were not seen in
our bullock.
DISCUSSION
In India there are two types of leishmania infection, firstly, the visceral
form caused by Leishmania donovani and known as kala-azar principally
C2