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e.—MORBID PHENOMENA PRESENTED BY THE URINARY SYSTEM.
The quantity of urine in the early stage of the disease does not appear to
vary to any great extent from that of health, but towards the latter end more
is passed ; but this must naturally depend to a large extent upon the amount
of water taken by the animal during the 24 hours, and upon the season of the
year.
Colour.—The urine of the horse in health, on being allowed to stand until
cool, is turbid and yellow in colour, carbonates of calcium and magnesium are
precipitated. After the inoculation of Surra, the urine remains turbid, and
becomes orange in colour, and later of a dingy green or greenish yellow ; if the
kidneys become affected, the quantity secreted is diminished, and the density
of the fluid is increased, and the colour changed to that of cream or a light yellow-
ochre ; the latter colour only lasts for a few days, four at the most, and then the
fluid assumes a greenish-yellow or dirty orange. In some horses the fluid
passed is very viscid, but not in all ; however in the case of mares it is usually so
from the first, and remains so, as long as the urine is alkaline, but immediately
the fluid becomes acid, the viscidity as a rule diminishes.
Specific Gravity.—The range observed in the specific gravity is very consi-
derable, and in the same animal may widely differ from day to day. In the case
of Horse No. LXXII (vide chart) it was as low as 1,004 on the 19th October
1892, and rose to 1,034 on the 20th, and 1,046 on the 23rd.
The highest registered in any case was 1,055—Horse No. XXVI—31st
October 1891.
The re-action of the urine of horses is always alkaline in health, but varies
according to the food given. In this country the urine of animals fed upon oats
is acid in re-action, while on the contrary when supplied with grass and gram the
re-action is alkaline. When a horse is the subject of Surra, especially in long pro-
tracted cases, the urine remains alkalineuntil some seven or eight days before death,
when it is found to change and become respectively feebly alkaline, at the ex-
pense of the Carbonates of Calcium and Magnesium, neutral on the following day,
then slightly acid, and finally strongly acid ; and this acid condition of the secre-
tion is maintained until death takes place; in some cases for as long as six days.
Urea.—The quantity of urea passed during the paroxysms and apyrexial
stages is at present under investigation. It appears however that the amount
of urea excreted, is increased to a considerable extent immediately after the in-
fusorian appears in the blood. During the paroxysms the amount undergoes a
slight decrease, rising again during the absence of the hæmatozoon from the blood.
It is a point of considerable interest that the maximum excretion of urea generally
takes place during the second intermissions, and after this period gradually
diminishes with perhaps a slight occasional rise, until the animal succumbs.
This question however, requires further investigation, and is now being carefully
worked out.
Uric acid is not increased in the horse, but in the ass it has been found
to be present previous to inoculation, and to absent itself after the appearance of
the hæmatozoon in the blood.
Phosphates are occasionally present, but in the great majority of cases are
totally absent in any appreciable amount.
Albumen.—This does not appear until some little time after the first
appearance of the hæmatozoon in the blood ; and then only in small quantities,
without the animal develops signs of the kidneys being specially affected. In case
XXXVIII the animal presented well-marked symptoms of the kidneys having
become involved. On examination of the urine, epithelial blood and granular
casts were found daily ; so that evidently the animal was the subject of an acute
disquamnative nephritis.
Sugar never found, although often examined for.
Bile pigments frequently present.
Retention and incontinence of urine have not been observed in horses.