23
SERUM.
19. Duration of Immunity.—When the protective serum is injected
subcutaneously for the purpose of granting immunity to an animal, the
chief points of importance are, to know what dose to give and for what
period we may look for protection against rinderpest in that animal. In South
Africa, serum in doses of 20 c.c. (10 c. c. per 600 lbs.) protected for about ten
days ; while the French observers discovered that in doses of 100 c. c. or more,
the immunity would be prolonged to two months (60 days) duration. The
hyper-immunised serum made use of at Muktesar was prepared between
the 24th February and 12th April 1899, and at the date of being utilised
(February 16th, 1900) had been kept at an elevation of 7,500 feet, during a
period of 10 or 11 months. The following experiment was therefore under-
taken with a twofold object; the first was to discover whether the serum
had lost any of its protective power against an attack of rinderpest, and the
second for what period would bovines injected with varying doses (10-200 c. c.)
of the above mentioned serum resist the effect of a dose of virulent rinderpest
blood, sufficient in an unprotected animal to cause a severe attack of the
disease, or even death.
Twelve plains animals obtained from the Terai, Bareilly District, North-
Western Provinces, were submitted to injections of protective serum on 16th
February 1900, as following :—
(1) Hissar cow (220), aged three years, computed body-weight 396 lbs.
Injected.—With 6.6 c. c. protective serum No. I, 10 c. c. per 600 lbs.
Testing.—On the 12th day after the serum injection, the animal was
inoculated with 1 c. c. of virulent rinderpest blood. Actual weight 403 lbs.
Progress.—On the evening of the sixth day after inoculation, the temper-
ature rose to 40.6°C. and varied between that and 41.3°C. on the 9th evening,
after which it fell to 38.8°C. Several small vesicles appeared on the gums,
otherwise there were no symptoms of rinderpest.
Remarks.—This animal evidently passed through an exceedingly mild
attack of rinderpest as evidenced by the presence of a few small vesicles.
(2) Hissar cow (142), aged three years, computed weight 415 lbs.
Injected—With 6.9 c. c. protective serum No. I, 10 c. c. per 600 lbs.
Testing.—On the 43rd day after the serum injection, the animal was
inoculated with 1 c. c. of virulent rinderpest blood. Actual weight 418 lbs.
Progress.—On the evening of the 3rd day after inoculation, the temper-
ature rose to 39.6°C. and later assumed normal limits, no symptoms of rinderpest
supervened.
Remarks.—This animal gave no reaction after 43 days from the date of
injection of 6.9 c. c. protective serum, and was therefore still protected.
(3) Plains bull (258), aged three years, computed weight 338 lbs.
Injected.—With 11.2 c. c. protective serum No. I, at 20 c. c. per 600 lbs.
Testing.—On the 43rd day after the serum injection, the animal was
inoculated with 1 c. c. virulent blood. Actual weight 351 lbs.
Progress.—On the evening of the 7th day after inoculation, the temper-
ature rose to 40.5°C. and then gradually fell to normal limits. The mucus
membranes presented a normal aspect and no symptoms of rinderpest super-
vened.
Remarks.—This animal was therefore protected after a period of 43 days.
(4) Plains bull (259), aged six years, computed weight 313 lbs.
Injected—With 10.4 c. c. protective serum No. I, at 20 c. c. per 600 lbs.
Testing.—On the 76th day after the serum injection, the animal was
inoculated with 1 c.c. virulent blood. Actual weight 337 lbs.
Progress.—On the evening of the 6th day after inoculation, the temper-
ature rose to 40.2°C. and on the following day recorded 40°C., after which it
fell. A slight purulent discharge from the sheath was noted, but the animal
fed well and rapidly put on flesh, for the body weight on the 13th day was
348 lbs.
Remarks.—A dose of 10.4 c. c. still afforded protection after 76 days.
(5) Plains bull (260), aged four years, computed weight 346 lbs.
Injected—With 29 c. c. protective serum No. I, at 50 c. c. per 600 lbs.