REPORT OF THE KING INSTITUTE, GUINDY.
15
ENCLOSURE.
Some observations on the production of cow-pox vaccine at The King Institute as shown
by the statistics during the last decade by Captain W. S. Patton, M.B., I.M.S.
As I have had the opportunity of observing the methods of making the cow-pox vaccine
at this Institute from August 1905 with intervals during which I was on leave or on special
duty up to the present time, it will, I think, be of some value and also of considerable interest
to examine the statistics for the ten years 1904 to 1914. Unfortunately the figures for the
earlier years are incomplete and those for 1906 were either not kept or have been lost. During
the earlier years—to be exact from February 1904 to July 1907—stock calves were used to
maintain the strain and the lymph obtained from these was transferred directly to the animals
used for the production of the lanoline lymph. As the number of calves required to meet the
increasing demand for vaccine increased, it was found expedient to mix the lymph from the
stock animals with glycerine in order to obtain sufficient seed to vaccinate the larger number
of calves. The stock calves were selected out of those brought by the contractors ; they were
kept separate and given a special diet. In 1907 the use of stock calves was given up by
Major Christophers, I.M.S., the then Director, for the main reason that it was considered a
wasteful method of maintaining the strain. Instead the animals showing the best vesicles
among the paste calves were selected during the day's inspection and the lymph so obtained
was mixed with glycerine and used for the manufacture of the lymph required for the issue
to the vaccinators of the Presidency. Up to the middle of 1909 the glycerinated lymph was
inserted on the paste calves in single lines but from this period it was inserted in groups of
triple lines of 30 to 35 such groups according to the size of the animal. The following tables
bring out some of the main points bearing on the production of cow-pox vaccine during the
years 1904 to 1914.
TABLE I.
Average yield of pulp per calf according to the months of the year.
—
January
...
...
...
...
...
February ... ... ... ... ...
March ... ... ... ... ... ...
April ... ... ... ... ... ...
May...
...
...
...
...
...
June ... ... ... ... ... ...
July
...
...
...
...
...
...
August
...
...
...
...
...
September ... ... ... ...
October ... ... ... ...
November ... ... ... ...
December ... ... ... ...
Grammes.
4.4
3.9
4.2
3.9
3.6
2.6
4.3
4.7
4.1
4.2
4.3
4.4
Maximum.
7.8
6.5
6.9
6.9
6.9
6.0
8.2
7.3
5.7
5.4
6.0
7.9
Minimum.
2.8
2.2
2.6
2.2
2.3
2.1
2.1
3.0
2.8
2.8
2.8
2.8
Table I shows the average yield of lymph according to the months of the year, and it
will be seen that although many of the calves produce excellent vesicles judging from the
maximum yield during the months of April, May and June, the average is distinctly low.
This is a clear indication that these months of the year are not favourable for the production
of cow-pox vaccine. During these months the vesicles are smaller, mature more rapidly and
then tend to dry up.
According to the available statistics 17,987 calves have been used during the period
under review, and the average production of lymph per calf works out at 4.1 grammes.