25
The latent period occupied three days. The Hæmatozoon was present in the blood from
the 3rd to the 9th August inclusive. After an interval of thirteen days it was again present
in small numbers for two days, August 23rd and 24th. After a second interval of nine days
it re-appeared for one day on the 3rd September. During a further period of 158 days
accompanied by daily microscopical examination of the blood, no organisms were observed.
The temperature became rapidly elevated after inoculation and attained a maximum of 41.4°C.
on the 4th day of the disease, and then gradually fell until the morning of the eighth
day when it registered 38.8°C. It again rose to 41°C. on the 37th day. The pyrexia, since
November 14th, has been characterized by morning remissions and evening exacerbations
especially on the 143rd, 155th, 156th, 168th and 178th days of the disease. During the
months of August and September this animal became greatly emaciated, but by December
had put on a considerable amount of flesh and appeared quite healthy.
On the 3rd September 1892, the 191st day after inoculation, and the 158th since the
last appearance of the organism in the blood, it was decided to re-inoculate the animals
with Horse Surra blood, in order to test whether any protection had been acquired from the
previous inoculation. Consequently on 9th February 1893 the animal was re-inoculated
sub-cutaneously with 2.0 c.cm. of blood drawn from the jugular vein of Horse No. LXXXIV
immediately after death, but which just before death contained numerous Hæmatozoa.
No swelling or œdema followed but there was only a slight thickening of the tissues
on the fourth day at the seat of the injection of blood. Three paroxysms occurred, viz., on
the 1st, 111th, and 233rd days, lasting 1, 3 and 3 days, with two intermissions occupying
109 and 120 days respectively.
The animal contracted rinderpest on the 26th September 1893, although isolated with
several other bovines in an enclosed area, surrounded by a wall 7 feet in height, and
succumbed on the 28th September.
Bull No. IV—was inoculated on July 27th, 1892, with 2.0 c.cm. of blood containing
the Hæmatozoon, taken from the rat (Mus decumanus) immediately after death. A considerable
amount of swelling and œdema followed at the seat of the injection which gradually decreased
in extent and finally disappeared about the 10th August 1892. From the 27th July until
October 10th, 1892, the blood remained free from the Hæmatozoon. On the evening of the 9th
September an urticarial eruption broke out on both sides of the neck, chest and scapular
regions, but had disappeared entirely by the following morning. On the morning of the 3rd
October, a similar eruption to the former made its appearance and again faded the same day.
On microscopical examination of the blood on the 11th October, the 76th day after inoculation,
a long and active trypanosoma was discovered, the dorsal membrane being particularly well
developed. From the latter date up to the 9th February 1893, the 121st day of the disease, no
further Hæmatozoa were observed, although serveral specimens of the blood were subjected to
careful microscopical examination daily. The temperature on the morning of the 8th day
following inoculation attained a maximum of 41 °C., but by the following morning had fallen
2 ° C., and although it subsequently, on numerous occasions, reached 40°C., it has only
risen to 40.3°C. From November 16th the pyrexia was characterized by marked morning
remissions and evening exacerbations, especially on the 55th, 56th and 59th day of the disease
when the morning and evening temperatures varied from 2.5°C. to 3.°C. (4.5 to 5.4°F). The
animal lost flesh during the months of August, September, October and November, but in
January 1893 began to put on flesh.
On February 9th, 1893, 197 days after the inoculation with rat's blood and 121
days after the first and last appearance of the Hæmatozoon in the blood, it was decided to
inoculate the animal with Horse Surra blood in order to test whether any protection had been
acquired from the previous inoculation. Consequently the animal was sub-cutaneously in-
oculated with 2.0 c.cm. of blood, containing numerous Hæmatozoa drawn from the jugular
vein of Horse No. LXXXIV immediately after death. No swelling followed at the seat of
the injection, but on February 14th the muzzle became hot and dry, and there was consider-
able fever,* lasting several days, but the Hæmatozoon was not discovered, although the blood
of the animal was collected and examined microscopically three times daily during the period
the fever lasted. On the 30th of April, 80 days after the re-inoculation, the Hæmatozoon was
observed in small numbers and remained in the blood for 48 hours, after which it disappeared
and was absent until the 18th July 1893, a period of 78 days ; when it was again present in
small numbers for one day. From this date until the 29th January 1894, a period of 195
days, the Hæmatozoon was never found, although daily examinations of the blood were made.
The animal unfortunately met with an accident, broke its leg, and consequently had to be
destroyed.
The chief points of interest in this case are that—
(i) This is the first case recorded of any animal of the bovine species having been
successfully inoculated with the Hæmatozoon of the rat (Mus decumanus).
Two guinea-pigs inoculated on the 21st September 1892 with 0.3 c.cm. of blood in which no Hæmatozoa
could be discovered microscopically, contracted Surra after a latent period of 14 days.
* It is possible that the Hæmatozoon was present in very limited numbers during the presence of the fever
between the 13th and 16th February 1893.
Two Guinea-pigs inoculated on the 21st September 1892 with blood from this animal in which no Hæmatozoon
could be discovered, failed to contract the disease.
E