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BLOOD PICTURE IN RANIKHET DISEASE OF FOWLS [Vol. XX, Part III
of erythrocytes and leucocytes, while blood smears for differential counts were made
by Wright's stain. The author correlated the alteration in blood picture with that
of changes in the diet of the fowls. Twisselmann [1939] observed that the supravi-
tally stained preparations, as compared to cover slip smears stained by Wright's
stain, give higher percentage of polymorphs, monocytes and basophiles and a lower
percentage of lymphocytes. Fluctuations in the figures of differential counts, made
by Wright's stained films prepared by slide method and cover slip method, were
slight. Whitby and Britton [1937] stated that leucocytosis was generally absent
in virus diseases. Physiological state of the subject at the time of taking blood,
the type of the film made, the method of making it and the method of counting
white blood cells, were some of the important factors the standardization of which
was stressed by MacGregor, Richards and Loh [1940]. It was further stated that
the slide method was the most popular owing to its simplicity and the ease with
which a good film could be obtained. ' Edge ', ' battlement ' and ' cross section '
methods of examination of blood smears were reported to be more common than
the method of random selection of fields for differential counts of leucocytes.
Monthly differential counts, of twelve Europeans, by these three methods revealed
that straight ' or ' edge ' count gave a consistently higher figure for polymorphon-
uclears than that obtained by the ' cross section ' count. As regards lymphocytes
the position was just the reverse. ' Battlement ' count showed a result between
the values obtained by random counting of 300 cells. Napier and Das Gupta [1940]
were of opinion that the slide method as advocated by MacGregor, Richards and
Loh [1940] was superior to the cover slip method, so far as the determination of
differential leucocyte count was concerned. McCarthy [1943] stated that the factor
of diurnal variation was not to be ignored while measuring concentration of hae-
moglobin in blood. Lewis and Shope [1928] and Kernkamp [1939] reported marked
leucopenia in swines suffering from natural and artificial infection of hog cholera.
Kernkamp reported that leucopenia was associated with distinct rise and fall in
the percentage of polymorphonuclears (heterophiles) and lymphocytes respectively.
He also observed leucocytosis in swines suffering from inflammatory diseases of
lungs and gastrointestinal tract but free from hog cholera. Severe leucopenia
was encountered by Hammon and Enders [1939] in cats suffering from a virus disease.
Distemper in ferrets was also shown to produce leucopenia by Kirk and Collins
[1945], while Verma [1947] experienced a similar phenomenon in rinderpest in goats.
MATERIALS AND METHODS
Birds of the same sex and approximately of the same age were employed through-
out. Fifteen known healthy Rhode Island Red male adult fowls were used during
the course of the investigation. Birds in cages were kept indoors in a well
ventilated room. The diet given to all the fowls was similar both in quantity and
quality. Diet was given twice a day. Water was constantly available in the cage.
Blood was always collected from the heart in the morning before the birds
were fed. The anticoagulant consisting of 2.4 mg. of potassium oxalate was used
according to the recommendation of Napier and Das Gupta [1940]. Heart blood
was collected in the following manner : One attendant holds the bird by the root
of its wings in the left hand and the legs in the right and puts the bird flat on a
working table. The operator with the bird in his right hand plucks the feathers