oloration of the mucous
membranes of the eyes, and a certain amount of swelling of the legs and
under surface of the belly. The diagnosis here can be made only by
microscopic examination of the blood. In strangles, equine variola, and
scalma we have an intensely red, rosy coloration of the mucous
membranes, full, tense pulse, and although in these diseases we may have
depression, we do not have the stupor and coma except in severe cases
which have lasted for several days. In influenza we have no evidence of
the formation of pus on the mucous membranes as in the other diseases,
except sometimes in the conjunctivae.

In severe pneumonia (lung fever) we may find profound coma,
dark-yellowish coloration of the mucous membranes, and swelling of the
under surface of the belly and legs; but in pneumonia we have the
history of the difficulty of breathing and an acute fever of a sthenic
type from the outset, and the other symptoms do not occur for several
days, while in influenza we have the history of characteristic symptoms
for several days before the rapid breathing and difficulty of
respiration indicate the appearance of the complication. Without the
history it is frequently difficult to diagnose a case of influenza of
several days' standing, complicated by pneumonia, from a case of severe
pneumonia of five or six days' standing, but from a prognostic point of
view it is immaterial, as the treatment of both are identical. The fact
that other horses in the same stable or neighborhood have influenza may
aid in the diagnosis.

_Prognosis._--Influenza is a serious disease chiefly on account of its
numerous complications. Uncomplicated influenza is a comparatively
simple malady, and is fatal in but 1 to 5 per cent of all cases. In some
outbreaks, however, complications of one kind or another preponderate;
in such instances the rate of mortality is much increased.

_Alterations._--The chief alteration of influenza occurs in the
digestive tract, and consists in hyperemia, infiltration, and swelling
of the mucous membrane, and especially of the Peyer's patches near the
ileocecal valve. The tissues throughout the body are found stained, and
of a more or less yellowish hue. There is always found a congested
condition of all the organs, muscles, and interstitial tissues of the
body. The coverings of the brain and spinal cord partake in the
congested and discolored condition of the rest of the tissues.

Other alterations are depende