16

REPORT OF THE KING INSTITUTE, GUINDY

material as possible in order to lengthen the life of the percolators. The results
of these investigations will be available when percolators on a large scale are con-
structed.

     (d) As a result of their various experiments, the Committee thinks that
with regard to both economy and the obtaining of a good effluent, percolation
followed by semi-rapid sand filtration is the method best adapted to purify water
at Kilpauk. The fact that the organic content of the raw water has increased in
the last two years, renders the adoption of some method such as this, aiming at
the preliminary removal of some of the organic impurity, still more necessary if
the present sand filters are to be used at all.

     Some other experiments for the Water and Sewage Purification Committee
were also done at Guindy on the effect of chlorination of raw water on the filter-
ing skin in slow sand filtration. No deleterious effect was observed.

     (6) Atypical water vibrios.—Mr. T. N. S. Raghavachari along with Mr.
S. V. Ganapathi Ayyar, Water Analyst to the Madras Corporation completed his
study of various atypical water vibrios isolated from the Red Hills Lake and
other sources in different parts of the Presidency. A paper was read before the
Medical Research Section of the Indian Science Congress at Allahabad. By their
serological reactions these seven strains can be grouped into two (1) the Red
Hills strain and (2) the other six.

     (7) Experiments on Soil Pollution.—Dr. J. F. Kendrick, who was working
on an Ankylostomiasis Campaign in Madras under the Rockefeller Foundation,
was anxious to get some data on the extent that various soils would transmit
bacterial pollution from faeces, and so asked us to collaborate with him. In two
places in Madras and Guindy respectively a central borehole was made and heavi-
ly infected with faeces and also at other times with B. violaceus and B. prodigio-
sus. Water was pumped from other boreholes surrounding the central one,
samples taken and examined by us. Dr. Kendrick who is now in Rangoon will be
writing a report. Briefly we may say that in the particular soils tested ordinary
faecal bacteria appeared not to be able to penetrate 20 feet of soil. The subject
is of great importance in connexion with the extended use of borehole latrines
which the Public Health Department are advocating.

     (8) A study of the factors causing degeneration of vaccine lymph on calf-to-
calf passages.—Drs. C. G. Pandit and K. P. Menon.

     It is well known that calf lymph deteriorates rapidly when passed in series
from calf-to-calf alone thus necessitating the passage of lymph on other suitable
animals, e.g., the rabbit. The factors which bring about such degeneration are
not well understood. In this connexion the role of contaminating micro-
organisms in the lymph is being studied. Detailed observations have been
recorded during the course of routine manufacture of lymph, on over 100 calves
involving five serial transfers. These observations will again be repeated during
the next working season when the data so obtained will be finally reviewed.

     (9) A study of various strains of Staphylococci isolated from vaccine lymph.—
Drs. C. G. Pandit and K. P. Menon.

     Staphylococci isolated from lymph from time to time were studied in detail
particularly with regard to their capabilities of producing exo-toxins. None of
the strains isolated so far have shown any evidence of exo-toxin production.

     (10) Persistence of vaccinia virus in rabbits after vaccination.—Lt.-Col.
H. H. King, Drs. C. G. Pandit and K. P. Menon.

     Rabbits which are vaccinated for seed passages during routine lymph
manufacture are usually kept under observation for one or two months after
vaccination. In November and December this year an unusually high mortality
was noticed amongst them. The rabbits which had been healthy suddenly died
of convulsions. An almost constant post-mortem finding was the presence of
areas of haemorrhage and broncho-pneumonic patches in the lungs. The role
of vaccinia virus in causing such mortality was investigated. Both microscopi-
cally and histologically, no evidence of meningitis or encephalitis was observed,
and subdural passages of the brain material from these animals into healthy
rabbits proved negative But by cutaneous scarification tests vaccinia virus was
found to be present in the spleen, brain and lungs of three out of 33 rabbits thus