46
REPORT OF THE IMPERIAL BACTERIOLOGICAL LABORATORY,
the various stages in its development to adverse circumstances, includ-
ing the action of such drugs as are ordinarily used in treatment. In
experimental conditions it was found that the average number of eggs
laid by an ovigerous female was seventeen to eighteen, and that 10 days
was the maximum duration of life of this female. The interval between
hatching of the larva from the egg and the attainment of adolescence
was 6 to 8 days. Ovigerous and pubescent females could withstand the
adverse influence of separation from their host better than could the
other stages; males and small larvae were most sensitive in this respect,
nymphs and large larvae intermediate. Exposure to sunshine prolonged
the viability of the various stages, while cold produced the opposite
effect. The action of 10 per cent. creosote in olive oil was fatal in 20
minutes at 31°C. for all males, nymphs, larvae, and the majority of
pubescent and ovigerous females.
With regard to the eggs it was found that the period taken for hatch-
ing varied from one to two days at summer temperature, and two to
three days at winter temperature. No egg separated from its host for
more than five days hatched subsequently when placed in the incubator
at 25-27°C ; after seven days at room temperature (10-13°C) no egg
hatched when placed afterwards on the host's body. Contact with 10
per cent. of creosote in olive oil for 30 minutes killed all eggs; only a few
survived exposure for 20 minutes.
Unfortunately the experiments could not be continued during the
1923-24 season, as the amount of material available, due to reduction
in the number of buffaloes used at Muktesar, was very small.
A paper was read on the subject by Mr. Timoney at the Fifth Ento-
mological Meeting, held at Pusa in February 1923.
(i) Tuberculosis. At the Second Meeting of Veterinary Officers in India
held at Calcutta in February—March,1923, a resolution was passed urging
the necessity for the prosecution of further research into the problem
of bovine tuberculosis in India. The information available would appear
to show that it is now a very rare disease of cattle in India, but some very
important questions remained to be solved in that there was not sufficient
knowledge available as to whether this rare incidence was due to a re-
latively high resistance of the indigenous breeds of cattle, or to a low
virulence of the infective organisms, or merely to the natural limitations
towards the spread of the disease in the conditions of cattle raising that
obtain in India. With the adoption of intensive methods of cattle
raising for economical ends, involving probably a large measure of cross
breeding with the most suitable imported breeds, it might well happen
that tuberculosis would become the scourge of cattle that it is in Western
countries. Hence, during one of my visits to Delhi in the cold weather
season 1922-23, the Director General, Indian Medical Service, and the
Secretary, Indian Research Fund Association, were interviewed upon
the matter, and a trained worker, Dr. M. B. Soparkar, was deputed by
the Association to collaborate with me in the investigation of the cogent
problems. He arrived at the laboratory in July, 1923, and facilities were