202
in the form of papers and memoirs during the years 1925 to 1928 form a
very complete record of the conditions in India with a careful statistical
analysis which brought out many important points. Roger's work on the
forecasting of cholera epidemics was also produced at this period. Other
epidemiological studies were made by Saranjam Khan in the United Pro-
vinces and by Gill and Lal in the Punjab in the years from 1928 to 1930.
3. During the years 1920 to 1927 the carrier problem and the bacterio- -
logy in relation to it was investigated on a large scale by Tomb and Maitre
and B. B. Brahmachari also contributed to this subject.
4. A new line of investigation on cholera was developed when d'Herelle
visited India in 1928 and took up the subject of the bacteriophage in rela-
tion to the disease. His work including that in collaboration with Malone
was followed by very extensive investigations on the subject by Morison
and also by Asheshov and his colleagues over a prolonged period of years.
All aspects of the bacteriophage in relation to the vibrio were studied and
trials were carried out on the value of bacteriophage in the treatment of
cholera. Field trials of the prophylactic value of bacteriophage were also
conducted on a very large scale.
5. The subject of prophylactic inoculation against cholera has been spe-
- c i a l l y s t u d i e d b y n u m e r o u s w o r k e r s — t h e p r o p e r t i e s o f t h e v a c c i n e a n d t h e
methods for its preparation have been specially investigated at the Central
Research Institute. Russell conducted .a large scale trial of the relative
value of parenteral oral vaccination under conditions which would yield
evidence of statistical value and showed the superiority of the vaccine used
in India for routine inoculation. Numerous other workers have also carried
out research on different aspects of the disease.
6. A new phase of cholera research has been in progress during the last
four years. The importance of cholera to India and the position which
India occupies as a potential source for the dissemination of cholera to
other parts of the world on account of its permanent endemic areas has
been accepted as a reason for undertaking very full investigations on the
subject with the object of further determining the causes of endemicity and
method of spread. A series of inquiries have been in progress whose work
has been co-ordinated by a Cholera Advisory Committee. In the first in--
stance the main line of investigation has been directed towards ascertaining
the characters of the vibrios obtained from cases carriers and external
sources, the vibrio being studied in relation to its source of origin and
epi-demiological circumstances of isolation. Investigations on these points have
been in progress at the School of Tropical Medicine and the All-India Insti-
tute of Hygiene, Calcutta; the Central Research Institute, Kasauli; the
Pasteur Institute, Shillong and the King Institute, Guindy. The work has
involved the study of the chemical constitution of vibrios, their metabolism,
biochemical reactions, phase lysability and other characters as well as the
study of variation. At the same time parallel studies on the vibrios have
been carried out in England by Gardner and Bruce White working under
the Medical Research Council. The dried O antigens of V. cholerae in
-cluding those of the Inaba and Ogawa types which have been prepared
and studied by these workers ha ve been the subject of extended trials in