8

REPORT ON THE WORKING OF THE KING INSTITUTE, GUINDY

Institute for the past three years. As a result of these experiments
sufficient evidence has now been collected to make a definite pronounce-
ment on the subject, and the result of the experimental work has been
reported to Government in this office letter Cur. No. 4218 of 1924. It is
not possible to give a detailed description of the various experiments that
have been carried out in this Institute as it would take up too much space
in this report, but a summary of the experiments and the conclusions
arrived at is given below:—

   "The following methods of purifying vaccine lymph have been
tested under the conditions which obtain in the Madras Presidency:—

(a) Chloroforming.
(b) Ether.
(c) Clove oil.
(d) Brilliant green.
(e) Untreated glycerine.

   The results obtained are as follows:—

   (1) Chloroforming lymph reduced the bacterial content to its
correct limits. Exposure of ten to twelve minutes produces least deterio-
ration in the potency.

   (2) Sterilization by ether.—So far tested by us, ether was found
to take too long, and to be uncertain in its effects.

   (3) Clove oil proved to be a satisfactory reagent for purification
purposes. The time required was four days' exposure and the amount of
deterioration of potency was small.

   (4) Brilliant green.—Brilliant green in dilutions of one in ten
thousand and one in five thousand, produced satisfactory bacterial purifi-
cation in about four days. The loss of potency was inappreciable. The
great disadvantage of this method is the extreme care that is required in
the addition of sodium hydrosulphite to stop the further action of
brilliant green.

   (5) Our tests show that glycerine lymph without any particular
treatment is purified to a satisfactory degree within four days of exposure
to the ordinary temperatures found in the Madras Presidency. As the
amount of deterioration in the lymph produced by glycerine is a common
factor to all methods of purification and as the more rapid methods of
purification may produce further deterioration, we see no advantage in
introducing any of these rapid methods. We therefore recommended
that no special means of purification be introduced and that untreated
glycerine lymph be the authorized lymph for issue to the Madras
Presidency."

   As the result of these experiments Government in their G.O. No.
Press 1972, P.H., dated 22nd December 1924, have approved of the use of
untreated glycerine lymph in this Presidency.

   (3) Tests with experimental lymphs prepared in various other ways.—
Experiments in connexion with the manufacture of dried lymph, orchitic
vaccine, and rabbit neuro-vaccine, referred to in the last year's report,
have been held in abeyance for the present, but will be resumed at a
future period. Experiments were made with crude pulp treated with
carbolised saline, with lymphs exposed to various temperatures for
varying periods, with lymph treated with arc-rays and also with dried
vaccine lymph. The results, however, were not so satisfactory as those
obtained with the usual stock lymph.

   It is most essential that every batch of vaccine lymph should be
tested from time to time during its storage, and before its issue to the
Presidency, with a view to ascertaining its potency. This is invariably
done on calves, but it is equally essential that a lymph manufacturing
centre like the King Institute should have always available near a
hand a sufficient number of human cases for vaccination and obser-
vation of results. For this purpose it is very necessary that some of the