MUKTESAR, FOR THE YEAR ENDING THE 31 ST MARCH, 1925
31
displayed at Muktesar. The bleeding rate of 8 c.c. per lb. body weight weekly appeared
to represent a drain that was not too heavy in the animal's system, and thus from a
buffalo of 700 lbs. body weight a quantity of blood amounting to over 44 litres, repre-
senting over 22 litres of serum (or 4,400" doses "), could be extracted during the remunera-
tive- period. After taking into consideration the initial cost of the producer (about
Rs. 35), and its cost of feed and keep during its maintenance for serum production (say
Re. 1 a day for 100 days), it may be safely assumed that further outlay of an expensive
nature upon so-called " hyperimmunization " cannot be considered worth while in the
light of the above information, and that the most economical and decidedly the most
humane course would seem to be to start afresh with new buffaloes after the stock of ani-
mals on hand had ceased to produce potent serum to meet current demands.
The Muktesar experimental work therefore seemed to warrant fully the establishment
of the system of serum production indicated from the above results as the routine method,
and for the operations at Izatnagar commencing with the beginning of the cold weather
season of 1924-25 a programme was laid on exactly parallel lines to the Muktesar large
scale experiment. 496 buffaloes were used in all during the season for the work. The
sera were returned for test to Muktesar, for storage and mixing for issue as indicated by
tests upon hill bulls. (The sera from the 1st, 2nd and 3rd bleedings were placed in
Barrel No. 1, from the 4th and 5th in Barrel No. 2, from the 6th and 7th in Barrel No. 3,
from the 8th and 9th in Barrel No. 4, and the 10th, 11th, and 12th were designated
" Barrel No. 5.") The " brew " of serum used in the Muktesar experiment was also
adopted for the inoculation of the Izatnagar producers simultaneously with the virus.
Some difficulty was found for some time in gauging the best dosage of this serum for
administration. In the first batch inoculated, the serum was given at the rate of 30 c. c.
per 600 lbs. body weight,—a dosage estimated from the Muktesar results to be a suitable
one; the temperature reaction in these buffaloes was, however, nearly " blocked out,"
and the serum forthcoming from the first bleedings of low potency. The dosage' was then
cut down to 20 c. c., and even then the serum obtained was not as potent as desired. After
cutting the protective dosage down to 15 and 10 c. c., the potency of the serum became
quite satisfactory. It would seem therefore that buffaloes during the cold weather in the
plains possessed a much higher degree of natural resistance towards rinderpest than
they had during the warm (but yet temperate) weather in the hills at Muktesar
(altitude 7,500 feet); this phenomenon has been noted before in the experience of the
laboratory, and deserves study.
The composite curve of the whole of the buffaloes used for serum production at Izat-
-agar is given in Chart IV.
The potencies of sera obtained from the consecutive bleedings upon test at Muktesar
were :—Barrel No. 1, 72.3 per cent.; Barrel No. 2, 83.4 per cent.; Barrel No. 3, 57 per cent. ;
Barrel No. 4, 62.5 per cent.; Barrel No. 5, 63.9 per cent. The more potent sera were then
mixed with the calculated quantities of the weaker sera for issue, so that the consign-
ments on test were all found to protect susceptible cattle with certainty at the guaran-
teed dosage.
Although information of great value had been obtained in connection with the princi-
ples underlying economic serum manufacture, there still remained many problems to
investigate connected with the detail of production. Notably, the question of the most
appropriate bleeding rates remained to be solved, especially in order to " draw off" the
maximum amount of serum while it is highest in antibody content. A question of even
greater importance is how to evoke with certainty the maximum " amount " of pyrexia
consistent with safety in the initial treatment of the producers. From what has been
stated above in connection with the reactions of the groups of buffaloes at Muktesar and
Izatnagar treated with the same " brew " of serum in the initial immunization it is not
easy to gauge a proper dosage of the controlling serum, so that the desired degree of
pyrexia is produced, when the serum is administered simultaneously with the virus.
The system of bleeding has been changed now somewhat as the result of preliminary ex-
periments. Also, based upon the assumption that the virus would get a better chance of
establishing itself so as to cause the animal's system to respond if it were introduced at an
interval prior to the fortification of the animal with anti-serum, tests have been carried
out in which producers have been given anti-serum simultaneously with, and one day,
two days, and later, subsequent to the introduction of the virus. It has been found that
the " amount" of safe pyrexia can be greatly increased by administering what would
just be a " blocking out" dose of serum if it were given simultaneously, one or two days
after the virus injection. The pyrexia shows a well marked increase in " amount"
B