MUKTESAR, FOR THE YEAR ENDING THE 31 ST MARCH, 1925
23
Much research was done at the laboratory during the year in developing the work of
producing " germ-free " filtrate. As has been stated above, the product issued in the
early stages to the field was the filtrate of a specially prepared broth culture, which was
very harmless even when injected in large quantities into guinea-pigs. Such cultures
have the drawback that they require some considerable degree of bacteriological skill
in preparation, and so, subsequently through the initiative of Mr. Haddow, the " ag¬
gressin " representing the filtered infected muscle juice was made on a large scale, for it
could be readily prepared without the application of much skill from the numbers of dis-
continued cattle available at the laboratory. This product, however, was found to
possess a high degree of toxicity for small animals and sheep, when made from local
strains and also from an authentic strain of Bacillus chauvoei obtained from the National
Institute of Type Cultures, London,—contrary to the statements of a number of authors
in this respect. The efficacy of vaccination with it has been tested on cattle and sheep
but the results are inconclusive—possibly because the method of testing the degree of
protection has been too drastic, as is believed to be the case in laboratory tests upon the
efficacy of hæmorrhagic septicæmia vaccine (the usual form issued consisting of dead
culture).
It was stated in the preceding Report that at the request of the veterinary authori-
ties in the Bombay Presidency steps were taken to manufacture supplies of protective
serum against blackquarter. This serum is now produced at the laboratory by the
repeated inoculation of cattle with the toxic muscle juice, and laboratory tests on cattle
indicate that it has a real efficacy. It is of especial value in cutting short virulent out-
breaks in infected localities. 6,835 doses (dose—15 c.c.) were issued and 4,686 were
prepared, as against 8,938 prepared only in the preceding year.
The publications of recent workers* upon this disease would seem to indicate that
veritable outbreaks of blackquarter in cattle are caused by one type of organism, namely
that which seems to have been figured originally by ARLOING and his co-workers and is
now known by English writers frequently as Bacillus chauvoei, and by German writers
sometimes as the rauschbrand bacillus or Bacillus sarcophysematos, among other names.
Disease indistinguishable from that caused by this organism may be set up by the nearly-
related bacteria which are the common causal agents of " gas-gangrene " in man, notably
the organism known as Vibrion septique by English and French authors, or the pararaus¬
chbrand bacillus or Bacillus parasarcophysematos and other names by the German writers,
but the disease does not always display the features of the common blackquarter as
regards enzooticity, and seems to attack animals mora commonly sporadically and often
as a sequel to wound infection.
The practical significance of this knowledge is that a protective agent which is effica-
cious against the common form of blackquarter need not be expected to ward off absolute-
ly any chance of disease occasionally arising which has the clinical appearance of black-
quarter in the animal. But, the evidence seems to be that such cases are relatively few,
and that special measures directed towards them are hardly worth while, and that a
sure prophylactic against the so-called Bacillus chauvoel will defend against outbreaks
of disease with the age-incidence, seasonal distribution, freedom from visible outward
mode of body invasion, and frequency in what are regarded as enzootic areas, that one
has learned to associate with the name " blackquarter."
(d) Anthrax serum. The number of doses issued was 48,405 (dose = 15 c.c.), as
against 29,834 doses in 1923-24; 67,717 doses were prepared, as against none in the
previous year. Towards the end of the year, researches were undertaken with a view to
revising the process of manufacture, following upon the lines of the researches already
prosecuted on the production of anti-sera for rinderpest and hæmorrhagic septicæmia.
These investigations are in active progress at the time of writing, and are already giving
promising results. In a country like India, intervention against the disease is usually
not undertaken except in the scene of actual outbreaks, and notably so among equines.
The administration of a good anti serum to animals exposed to danger would appear
to be the mode of intervention most susceptible to bring about a rapid disappearance of
the outbreak in such cases, and field experience seems to bear out this view.
*See, among others : GAIGER, Anærobic Infections in Animals, Jl. Comp. Path. o
Ther., 1924. Vol. 37 p. 163, and WAGENER, Die Diagnose des Rauschbrandes.—Arch.
f. wiss. u, prakt Tiaheilkunde, 1925 Vol. 52, pp. 73-179.