MUKTESAR, FOR THE YEAR ENDING THE 31ST MARCH, 1925
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blood is taken from relatively insusceptible cattle for the inoculation it may be devoid of
virulence when used after a few hours ; it has indeed transpired that some cattle subjected
to the inoculation in former years contracted the natural affection during recent outbreaks,
due undoubtedly to the blood used for the immunization not possessing any virulence.
The information obtained from many laboratory researches, that the blood taken from
an infected animal retains its virulence for three times at least the period during which
it does so when it is allowed free access to air if the sample is placed at once after with-
drawal in hermetically sealed sterile containers, led to the adoption of a method of des-
patching virulent blood in this manner by the postal service. Hence, during the cold
weather of 1924-25, blood was despatched to veterinary authorities who wished to carry
out the serum-simultaneous inoculation in small sealed bottles (one-ounce sterile bottles,
with waxed wool plugs) from the Izatnagar branch laboratory, and " controls " ino-
culated in the Madras Presidency showed that the blood was highly virulent on receipt
after 7 and 8 days. Specially manufactured " brews " of serum, from the early bleedings
of buffaloes, were also sent from the branch laboratory for the inoculation. Records are
available concerning 1,422 cattle immunized during the season. There was a mortality
of 14, largely accountable for by the accidental development of acute piroplasmosis in
animals bred in areas free from this infection. In one herd in Assam, inoculated by
Mr. Cooper, four succumbed to Piroplasma bigeminum infection, and unfortunately the
sample of trypanblau used by him to counteract the complication produced disturbing
symptoms. Some young buffalo calves succumbed, due apparently to the administra-
tion of an insufficient dose of serum.
On the whole, it seems that there is sufficient evidence available for the intensive
propagation of the method throughout India, especially on young indigenous cattle, and
it seems that the system instituted at the Imperial Cattle Breeding Farm, Karnal, is
well worthy of emulation, whereby the inoculation is to be applied at half-yearly intervals,
to all cattle under two years of age that have not been protected. The higher resistance
of young cattle towards the complicating effects of piroplasmosis points in favour of this
system. Nevertheless, it is hoped that work in progress at the laboratory will soon cul-
minate in the production of virulent material for the inoculation free from piroplasms or
other harmful contaminating organisms.
(b) Hæmorrhagic septicæmia serum and vaccine. The demands for these products
remained fairly steady. 2,79,061 dqses (dose=15 c. c.) of serum were issued, as compared
with 2,21,174 doses in 1923-24. The quantity manufactured was 4,56,566 doses, as com-
pared with 2,53,004 doses in 1923-24. The number of doses of vaccine issued was
2,12,600, as against 1,77,600 doses in the preceding year. The vaccine is prepared
fresh to meet demands, and hence no considerable stocks are kept on hand.
The large excess stocks of serum were manufactured to meet the anticipated demand
of the next period of increased seasonal prevalence of hæmorrhagic septicæmia, namely,
the rainy season. In the past, the process of manufacturing this serum had been a rather
costly one. The method adopted followed closely the plan generally pursued in manu-
facturing an immune serum, by " hyperimmunization" of suitable serum producers, which
were found to be buffaloes in the experience of the laboratory. The steps in " hyperim-
munization" consisted in inoculating the producers initially with a small dose of
live culture and a suitable dose of anti-serum to protect the animals against risk from the
effects of the culture ; subsequently, the animals were injected with gradually increasing
doses of culture alone at intervals of about a week, and in about six weeks' time they were
considered fit to be bled at a suitable rate for the production of the immune serum. They
were then injected at intervals of about a fortnight with the largest dose of culture already
given, and bled some days after each inoculation. The live cultures used were "passaged"
frequently through rabbits in order to maintain them, it was believed, in a state of
virulence for bovines, for it was thought that the maintenance of a high degree of viru-
lence was an essential property of a good antigen. At the commencement of the year
under report, when the knowledge then available did not justify any departure from the
established system, it was thought that perhaps large hill bulls would be more suitable
as producers, for the buffalo's constitution seemed relatively delicate and particularly
susceptible to the rigours of the cold weather in the hills. On the other hand, the locally
bred hill bulls thrive well when properly fed in these conditions, and hence it was believed
that it would be economical to use them as they would be much more likely to survive
through the cold weather from one year to another, for the process of preparing afresh
at the commencement of the warm weather in the hills a new series of producers was a
rather costly and slow one. The main drawback to the use of bulls apart from their
smaller size, is that all their plasma has to be separated artificially by centrifugation of
the oxalated blood, for the corpuscles show very little tendency to separate spontaneously