44 DISEASES OF DOMESTICATED BIRDS 
White rats die after intraperitoneal inoculation, but subcutaneous 
inoculation may fail. 
Morbid anatomy. Severe pericarditis is one of the most no- 
ticeable characteristics observed at autopsy. The pericardium may 
show extensive adhesions to the heart wall, and the latter may be 
covered with a layer of yellow colored fibrinous exudate. The peri- 
cardial sac may contain sero-fibrinous exudate. The lungs show 
pneumonic changes and are frequently completely hepatized. Be- 
yond possible fatty changes in the liver and paleness and swelling 
of the kidneys, changes in other organs are not marked. 
Microscopic examination of blood smears from heart blood, peri- 
cardial exudate, lung and various organs, reveals the presence of a 
bipolar rod. : 
Relation of disease to fowl cholera. M’Fadyean believes that 
the effects produced on various animals by the organism described 
by him, warrant the differentiation of the disease from fowl cholera. 
He notes that pericarditis and pneumonia occur in fowl cholera, but 
not with such constancy as they occur in the disease described by 
him. 
AN EPIZOOTIC AMONG FOWLS 
Mazza reported upon a disease that caused heavy mortality in 
various parts of upper Italy. 
Etiology. Cultures from various organs almost always yield 
growth of a motile rod, while culture media seeded from exudate, 
blood and brain are more often sterile. Mazza concludes that the 
organism differs from that of fowl cholera in several particulars. 
It is larger than B. avisepticus, does not usually exhibit bipolar 
staining, is motile, is not very pathogenic for rabbits-and is rarely 
observed in the blood. 
Pathogenicity. Hens and pigeons succumb to the infection 
without exception. Guinea pigs are completely insusceptible while 
rabbits are very slightly susceptible. 
Symptoms. In general the hens die suddenly during the night 
without having previously shown distinct symptoms of disease. In 
other cases, symptoms like those occurring in fowl cholera are ob- 
served. 
Morbid anatomy. In external appearance the fowls usually 
show no signs of emaciation. The only abnormal conditions en- 
countered are darkening of the comb and large red areas on the skin 
of the abdomen and of the breast. The subcutaneous cellular tissue 
