REPORT OF THE KING INSTITUTE, GUINDY
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PART II.—SCIENTIFIC AND GENERAL.
(A) VACCINE LYMPH.
1. Charge of work. —The Assistant Director Dr. C. G. Pandit was in charge
of the section throughout the year.
2. Seed lymph. —The Nijland's method of maintaining the potency of seed
lymph was adopted by this Institute in 1922. The practice hitherto had been
two fold—(i) to pass the lymph through a continuous and regular sequence of
animals (rabit-buffalo-calf) and (ii) later also to maintain it on calves alone till
signs of degeneration were manifest when it was again revived by such animal
passages. The latter method was not adopted this year as it was found on
analysis of the results from the Presidency that better case success rates were
always obtained with first type of lymph. This year therefore only buffalo lymph
was used as seed lymph for the vaccination of calves. The hot weather passages
of seed lymph have also been continued. On account of this continuous and
regular passage of seed lymph throughout the year and on different animals
6 strains of seed lymph have been continuously maintained in the Institute for
over two years without any appreciable loss of potency being manifest.
3. Potency.—The question of potency was discussed in detail in the annual
report of the last two years, particularly that of 1926-27 (vide paragraph 3,
page 3). As a criterion of potency the vesiculation test introduced by Majors
Cunningham and Cruikshank was found to be quite reliable. As was then pointed
out highly potent lymph gives continuous lines of vesiculation with 1—500 dilution
of the virus. As was the case last year, all the "cups" manufactured gave
continuous lines of vesiculation with this dilution.
In 1927 under the Therapeutic Substances Regulations, the Ministry of
Health in England laid down the following definite standard of potency for
vaccine lymph :—"The thousandfold dilution of vaccine lymph shall be tested
. . . on rabbits and guinea pigs and lymph from which the dilution was
prepared shall not be issued unless the characteristic lesions due to vaccinia virus
are produced in the test."
For comparison this procedure was also adopted this year with the majority
of cups manufactured. The dilutions (1—1,000) of lymph were tested both on
calves and rabbits with quite satisfactory results. It was indeed very gratifying
to note that with such high dilutions as 1—1,500 of vaccinia virus and following
the usual vesiculation test technique, over 60 per cent of cups manufactured gave
"continuous" or "almost continuous" lines of vesiculation.
The Saidapet range results show a slight decrease over last year's figures, viz.,
99.4 per cent case success rate and 95.3 per cent insertion success rate as against
99.6 per cent and 97.0 per cent respectively. On the other hand general case
success rate in the Presidency is 97.4 per cent which is higher than last year and
is also the highest on record in the Presidency.
4. Purity.—All the lymph issued was examined bacteriologically and by
animal inoculation and other tests, and none was found to contain any patho-
genic micro-organisms. As regards purity the lymph issued satisfied all the
requirements laid down in the Therapeutic Substances Regulations referred to
above.
5. Yield of pulp.—The average yield of pulp this year was 23.9 grammes per
calf as against 23 . 7 last year. In all 1,058 calves were utilized out, of which 172
were rejected for poor vesiculation. As had been the procedure for the last two
years attempts were made to manufacture the bulk of vaccine lymph during the
colder months of the year.
6. Off season.—Routine vaccination was suspended in all the districts in the
Presidency except the Nilgiris and Shevaroy Hills for four months during the hot
weather. The periods of suspension were the same as last year.
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