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f.—MORBID PHENOMENA REFERABLE TO THE ORGANS OF SPECIAL SENSE.
(i). —Organs of Vision.
Lachrymation.—This at first is slight, but in some animals rapidly increases
in amount until it becomes profuse. At a varying period in the disease, there
appears at the inner canthus a semi-gelatinous secretion, which may become
muco-purulent in character, and during the presence of the hæmatozoon in the
blood in large numbers, slight hæmorrhages take place from the conjunctival
membranes, and the secretion becomes blood-stained. At these times it always
contains the hæmatozoon in varying numbers.
Petechiæ.—This is not the only disease in which petechias, or more extensive
extravasations occur ; for they are usually present in anthorax, so-called bilious
fever, petechial fever, and other diseases ; also when an animal is suffering from
the presence of small nœmatodes in the general circulation. In ' Surra' the
petechiæ on the conjunctival membranes are specially prone to invade the mem-
brana nictitans of the equidæ, and frequently attain a large size, becoming
relatively extensive extravasations, they may precede the discovery of the hæma-
tozoon, but as a rule are found shortly after the first appearance of the organism
in the blood, and commence to fade immediately it disappears ; and as each
successive brood of the hæmatozoon make their debût, a fresh crop of petechiæ
appear on the membranes, and it often happens that a second series of petechiæ
are present before the first have completely faded.
Opacity of the Cornea.—Complete opacity is of rare occurrence, but towards
the termination of a long case, a slight milkiness of the cornea may be observed,
and is not at all infrequent. I have, however, seen one case in an Arab horse,
where complete opacity occurred a few days before death, and therefore blindness
supervened.
Hæmorrhages into the anterior chamber occasionally occur, but the amount
of blood is generally small. The colour at first is red, and after a period of 24
hours or more, the colouring matter is absorbed, leaving the extravasated mass
either of a whitish hue, or somewhat yellow in the case of an animal in which
the membranes are already tinged that colour. As a rule no absorption of the
extravasated material takes place, owing to the short period which elapses between
the occurrence of it and death.
Hæmatozoon in the fluid of the anterior chamber and Vitreous Humour.—On
several occasions the presence of the ' Surra' organisms has been verified in
both of these fluids.
(ii).—Organs of Smell.
Discharge from the nostrils.
Ulceration inside the nostrils.—One observer, Steele, mentions the occasional
occurrence in mules, of ulcers on the Schneiderian membrane, when the epithelial
debris remains as a yellow scab for a day or two, and is then washed away by
mucus ; the earliest appearance of these ulcers in the nose is as though the mem-
brane had been grazed, and blood was slowly oozing; they rapidly disappear
and the general character of the membrane becomes normal. I have not
observed these, however, in the cases of naturally acquired, or in the inoculated
cases of Surra.
Petechiæ and injection of the nasal septum.—The presence of minute petechiæ
on the walls of the septum nasi is of very constant occurrence. The mucous
membrane covering the cartilage is tumefied, and presents small red points from
which minute drops of blood exude ; these appear as if they might have been
produced by punctures of a large number of needles, so minute are they. This
condition does not show itself until the animal has been ill for some days, and
then they might be easily overlooked without a certain amount of care in
observation,
Thickening and intense tumefaction of the Schneiderian membrane.—This con-
dition is frequently met with, more especially at an advanced stage of the disease,
A. peculiar sound is produced by the entrance of air, and its exit from the nasal
passages, due to the swollen condition of the mucous membrane lining the