160 SYNOPSIS OF CONTINENTAL VETERINARY JOURNALS. 
horses, pigs, and cattle, that of the latter females are the 
most subject; that sheep and goats seem to be absolutely 
exempt from it; lastly, that it is in middle and advanced 
age that predisposition to it is most marked. The cause of 
the disease is profoundly obscure, and the relation which in 
some cases seems to exist between its appearance and a 
condition of injury, must be considered simply as one of 
coincidence. The pathological alterations consist, then, in 
augmentation of the number of white blood-corpuscles in 
proportion to the red, they being 1 to 10 or 20. All the 
blood-making organs are hypertrophied, especially the spleen, 
all of whose elements contribute to the increase in volume. 
The true hyperplasia of this organ is probably the result of 
a prolonged hyperaeniia, and according to the stage of disease 
the organ is soft and distended with blood, or firmer, and 
containing less blood. This hypertrophied organ generally 
preserves its normal form, but its margins become rounded, 
and its surfaces rough from the thickening of its fibrous 
capsule. Its increased consistency makes it something like 
liver substance, and the splenic tissue on section appears 
granular. The cut surface is always dry, of a pale red or 
uniformly bluish tint, and sometimes the enlarged Malpig¬ 
hian corpuscles, having acquired the size of a pea, are pro¬ 
jecting from the pulp substance. The stroma gradually 
contracts and forms thick trabeculae extending from the 
equally thick spleen capsule; sometimes haemorrhagic 
patches are present. The microscope enables us still to 
recognise the normal spleen elements, but the reticulated 
tissue is thickened and nodose near the haemorrhagic 
patches. The fusiform cells which are often met with show 
also the presence of a cellular hyperplasia of the areolar 
stroma. The lymphatic glands sometimes, though rarely in 
domesticated animals, become by their liyperplasy the origin 
of leucaemia, and then either all or some of them become 
enlarged and rounded. Their substance appears against 
their smooth and distended envelopes, and becomes very 
prominent on sections. The marrow, as well of long 
as of spongy bones, is the seat of similar changes, and 
assumes the characters of embryonic tissue. In conse¬ 
quence of the invasion of leucaemic infiltration, other organs, 
as the kidneys and the liver, may have their connective 
tissue replaced by lymphoid tissue. The author has met 
with such infiltrations of the walls of the vessels and of the 
mucous canals. They commence in the submucous areolar 
tissue, and there form a soft layer, indefinitely extended, of 
reddish-grey embryonic tissue. The symptoms of the dis- 
