314 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [VI, IV

While studying the diphtheritic form Moore [1885], Marshall [1900] and
Jackley [1918] were of opinion that bacteria might be the cause but could not
confirm their identity. Jowett [1909] stated that comb and mouth lesions were
etiologically distinct. Ward [1904] was the first to relate roup etiologically to
chicken-pox. Haring and Kofoid [1911] demonstrated cell inclusions of chicken-
pox in the cheese-like lesions of the mouth and throat of fowls. Hadley and
Beach [1913] believed that the head and mouth forms were different manifesta-
tions of the same disease. Mack and Records [1915] showed evidence that chicken-
pox and avian diphtheria were etiologically identical but did not draw positive
conclusions. Arloing [1911-12] differentiated false and true fowl-pox diphtheria
by histological methods. Jackley [loc. cit.] while studying roup, incriminated
an organism of the Pasteurella group. Beach, Lothe and Halpin [1915] showed
in an outbreak of chicken-pox and avian diphtheria that the high mortality was
due to secondary invading bacteria although the primary cause was a filtrable
virus. From the study of Brumley and Snook [1916] it seems that although there
is a virus and complicating conditions induced by secondary bacterial infection,
neither factor alone would cause a typical disease. Doyle and Minett [1927]
studied the identity of wart-like growths on the head and diphtheritic lesions
in the mouth and confirmed that comb and mouth lesions in the case of fowl-pox
were due to the same virus and immunity to one form could be set up with
material from another form. There was no evidence that bacteria alone could
produce typical mouth lesions, the primary action of the specific virus being
essential.

                                  PURPOSE OF EXPERIMENTS

Experiments have been conducted to study the transmissibility of the virus
of the diphtheritic lesions, its tendency for generalization, its etiological identity
with the ordinary cutaneous form of fowl-pox as commonly found in India, filtra-
bility of the causative virus and its immunological identity with our stock fowl-
pox virus, which was obtained through the courtesy of the Veterinary Laboratory
of the Ministry of Agriculture, Weybridge, England.

                      METHOD OF EXPERIMENTAL TRANSMISSION

A specimen of crusts was powdered and a 1 per cent emulsion was made
after the method of Doyle and Minett [loc. cit.] with a slight modification that
instead of ordinary saline, 80 per cent glycerinated saline was used in its prepara-
tion. The inoculum thus prepared was applied by means of a swab over a scari-
fied portion of the comb in the case of cocks, and in other birds over the feather
follicles of the leg after pulling out a few feathers. Two healthy fowls and a
fowl immune to our stock fowl-pox virus (Weybridge strain) were used for each
specimen and the results were reported after a fortnight's observation from the