H. N. RAY AND K.
RAGHAVACHARI
29
ausculatation ; vomiting of mucus ; bloody diarrhœa. On autopsy the dog
showed the following changes : the lungs at certain places were oedematous
and showed very minute nodular lesions, at which there were accumulations
of the parasites ; there was hyperplasia of the interlobular connective tissue ;
the spleen was only slightly enlarged; the liver was enlarged and showed
lesions similar to those in the lungs ; the kidney was congested but the pancreas
was normal; the mesenteric glands were slightly hypertrophied and found to
be blood-tinged on section ; the yellow marrow of the long bones was trans-
formed into red marrow ; the blood in the heart and vessels not coagulated ;
the erythrocyte count was 1,800,000 per cubic mm.; the blood showed anæmic
changes as indicated by the presence of poikilocytes, macro- and micro-cytes
and a few megaloblasts ; leucopenia was marked ; differential counts of the
leucocytes revealed polymorphonuclear 40 per cent, mononuclear 29 per cent,
transitional 15 per cent, lymphocytes 16 per cent and eosinophile 0. The
parasites were found in the smears of spleen, lung, liver and bone marrow.
The endoglobular forms of the parasites situated within the cytoplasm of the
monocytes are described as crescent-shaped and measuring 1.2µ in length
and 0.5µ in breadth. The multiplication is said to take place only by
longitudinal binary fission.
Yakimoff and Kohl-Yakimoff [1911] encountered Toxoplasma canis in
smears from the organs of some dogs. The parasite is described as having
two modes of multiplication, viz. binary fission and schizogony.
Carini [1911] was able to reproduce the infection by the inoculation of
suspension of liver tissue from a dog that had died of toxoplasmosis. Accord-
ing to his observations the organs affected were the lungs, liver and spleen.
The parasite which caused these lesions was identified by him as Toxoplasma
cuniculi. A tissue suspension of the infected organs when inoculated into
pigeons and rabbits produced toxoplasmosis with typical lesions and they
died within 15-16 days and 7-9 days respectively.
Carini and Maciel [1913] have described natural cases of toxoplasmosis
in dogs and they are of the opinion that Toxoplasma cuniculi and Toxoplasma
columbae are morphologically indistinguishable from Toxoplasma found in
dogs. It has been remarked that, as the pathogenic picture presented by
Toxoplasma cuniculi is identical with that in Toxoplasma canis infection, it
is doubtful whether the two parasites should be considered as separate species.
Laveran [1913] was able to produce toxoplasmosis in a dog by inoculating
the peritoneal exudate of a rat showing Toxoplasma gondii. He noticed corneal
opacity in this dog and is of opinion that Toxoplasma gondii, Toxoplasma
cuniculi and Toxoplasma canis are not different from one another and that
they should be considered as belonging to one species.
Blanc [1917] described three cases of toxoplasmosis in dogs in Tunis
and in one of these he observed conjunctivitis and corneal opacity.
Boez [1921] reports spontaneous toxoplasmosis in dogs and claims to
have seen schizogony of the parasite, in addition to its usual mode of multi-
plication by binary fission. The schizonts, according to his observations,
mostly develop extra-cellularly in the lungs in the vicinity of the alveolar
capillaries. The schizonts included in the cytoplasm of the macrophages
can be distinguished from the others. Transmission experiments by inocula-
tion of pulmonary nodules gave negative results.