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(ii) Will a calf suckling its mother, under such conditions, contract the disease ?
A cow, with a calf three weeks old at her side, contracted Surra.* The blood of the mother was
found to contain the hæmatozoon for a period of 120 hours.
The calf was allowed to suckle three times in the 24 hours, and the milk from each teat was daily
examined microscopically for the presence of the organism; but this was never discovered. On the
38th day from the appearance of the hæmatozoon in the circulation of the mother, it appeared in the
blood of the offspring, which up to that date had been free. The organism remained in the circulation
for 24 hours only, and had not re-appeared 123 days later. Blood in small quantities must have become
mixed with the milk, owing to rupture of some small mammary vessels and by this means the hæmato-
zoon entered the digestive tract of: the calf.
On February 9th, 1893, the calf having grown considerably and being in good condition, it was
decided to re-inoculate it, with a view to ascertain whether the animal had received any protection from
the presence of the Trypanosoma in its circulation. Consequently, the same evening the calf received
subcutaneously 1.0 c.c. of blood taken from the jugular vein of Horse No. LXXXIV immediately
after death. No local manifestation followed the injection at the seat of the injection. The latent
period occupied a little over 3 days, the hæmatozoon being present for two days, February 13th and 14th
and again for one day (18th) after an intermission lasting 72 .hours. From the 18th February until
September 30th, 1893, a period of 224 days, the organism was present in the blood once and then only
for a few hours, viz., on the 22nd June, 123 days after its last appearance.
The animal contracted rinderpest, the first symptom appearing on the 28th, and succumbed to that
disease on 30th September 1893.
A similar experiment with the same end in view, as in the case of its offspring, was initiated in the
cow. It was re-inoculated on the 9th February 1893, with 2.0 c.c. of blood containing numerous
hæmatozoa taken from the jugular vein of Horse No. LXXXIV immediately after death. The latent
period occupied 8½ days, no local manifestations being observed at the seat of the injection. From the
first appearance of the organism in the blood, on the 18th February 1893, until 31st May 1894,
6 paroxysms, each lasting 1 or 2 days, occurred, the hæmatozoon never exceeding two in a field of the
microscope. The length of the intermissions was 10, 29, 70, 9 and 128 days, but as the examination of
the blood was discontinued on May 31st, 1894, 214 days since the last appearance of the organism in the
blood, it is very unlikely that the hæmatozoon would have again appeared in the circulation. On this
latter date the animal was in good health and in very fair condition.
SECTION III.
Buffalo Surra following inoculation, including the case of Bull No. V at an elevation of 7,500 feet.
Up to the time these experiments were undertaken there was no evidence forthcoming to show
whether buffaloes are susceptible to the organism of Surra or not, although it was surmised that if bovines
were capable of contracting the disease buffaloes would not be exempt. We had previously shown that
bovines passed through an attack of Surra, and if the disease was uncomplicated with any other, the
animals always survived, even when re-inoculation was resorted to after varying periods.
In our previous researches, the experiments were conducted more or less in the plains ; consequently
when these investigations were initiated on buffaloes in the hills, at an elevation of 7,500 feet, it was
decided to ascertain concurrently what effect, if any, was produced on bovines by the change of tempera-
ture, &c. The opportunity was also taken of working out certain physiological and pathological problems
as far as circumstances would permit, on very much the same lines as those adopted in the case of
equines, a précis of which was included in the last Report for 1895-96. In order to make this enquiry
in bovines and buffaloes, the quantity and composition of the ingesta and egesta have been ascertained
during a period of observation previous to inoculation, the incubatory period of the disease, and the
paroxysms and intermissions until death. The following data were recorded, viz :—
The weight and composition of the ingesta including fodder and water, also that of the egesta
including dung and urine.
In the urine the total nitrogen, the urea, the hippuric acid, and ammonia were separately estimated.
Bull V.—(Hill animal) aged 2 years, was kept under observation from the 27th November 1896
until 15th February 1897. On the 16th February it was inoculated on the ear, a minute incision being
made and a trace of blood containing a few hæmatozoa taken from Buffalo I was placed between the edges
of the wound. The latent period occupied six days. The hæmatozoon was present in the blood from the
1st to the 3rd of March inclusive. After an interval of three days it was again present in large numbers
for four days, March 7th to the 10th ; after a second interval of five days it re-appeared for one day on
the 16th March. During a further period of 147 days accompanied by daily microscopical examinations
of the blood, no organisms were observed. During the period of observation lasting 89 days, the tem-
perature varied between 39.3° and 36° C., and between 38.9° and 37.1° C. during the latent period of the
disease. On the appearance of the hæmatozoon, the temperature became rapidly elevated and attained
a maximum of 42.5° C. (108.5° F.) on the third evening, and then gradually fell until the morning of the
* During the latent period there was no swelling or œdema observed at the seat of the injection of blood, although a slight
thickening could be felt in the subcutaneous tissue.