4

REPORT OF THE KING INSTITUTE, GUINDY

PART II.—SCIENTIFIC AND GENERAL.

(A) VACCINE LYMPH.

       1. Charge of lymph.—The Assistant Director Dr. C. G. Pandit was in charge
of the section throughout the year and has collaborated in writing this portion of
the report.

       2. Seed lymph.—Reference—last year’s report, page 3, paragraph (2): this year’s
experience has confirmed last year’s findings on the desirability of continuing the
passage of seed lymph in the hot weather. It is now proposed to adopt this as a
routine procedure. An attempt was made to substitute donkeys in place of
buffaloes in Nijland’s cycle, i.e., to adopt rabbit donkey calf passages instead of
rabbit buffalo calf ones. It was found, however, that donkeys were not as
susceptible to vaccinia virus as buffaloes or calves, none of the animals vaccinated
showed a typical “ take,” the reaction was considerably modified and scabbing
well marked at the end of 72 hours.

       3. Potency.—The question of potency of vaccine lymph was discussed in
great detail in last year’s Annual Report (vide paragraph 3, page 3). It was
pointed out that the main criteria of potency were the results of vesiculation tests
and the vaccination rates in children.

       Highly potent lymph gives continuous lines of vesiculation on calves with
“ 1/500 dilution ” of the virus. The percentages of such “ continuous ” cups to
the total manufactured for the last six years are set out below:—

       Thus the maximum potency was reached this year.

       On the whole the vaccination rates also show an improvement over last
year’s figure. The cup test rates in the Saidapet range, i.e., the results of vacci-
nation with cups soon after manufacture, were not quite as good as last year,
being 99.9 per cent case success and 97.7 per cent insertion success against 100
per cent case success and 99 per cent insertion success last year. On the other
hand, the general results in the Saidapet range were 99.6 per cent and 97.0 per
cent case and insertion success rates, which are better than last year’s figures
of 99.3 per cent and 96.5 per cent respectively, and further as will be shown later
the results throughout the Presidency were a little better this year than last,
yielding the highest case success rate on record in this Presidency.

       4. Purity.—All the cups manufactured were examined bacteriologically and
by animal inoculation and were not found to contain any pathogenic organisms
of importance.

       5. Yield of pulp.—The average yield of pulp this year was 23.7 grammes per
calf as against 23.05 last year and 23.5 the year previous. This slight increase in
yield is in line with the slight increase in potency. In all 1,082 calves were
pulped and 147 rejected for poor vesiculation. It has been our experience that
best yields are obtained in the months of December, January and February, the
average yield for these months being over 25 grammes. Not only is the yield
better, but the quality of lymph is also superior in these months. So attempts
are always made to manufacture as much lymph as possible during these months.

       6. Off season.—Vaccination was suspended for four months during the hot
weather in all districts except the Nilgiris and the Shevroy Hills. The periods of
suspension were the same as last year.