72 DISEASES OF DOMESTICATED BIRDS 
soon after hatching and continue to the third or fourth week. 
Chicks which survive, remain stunted and unthrifty for some time. 
Morbid anatomy. The lesions observed on autopsy are not 
clearly distinctive for this disease which is purely septicemic in 
nature. The early, rapid development of the disease, in a host 
unprepared to combat it, prevents the formation of many distinctive 
lesions. The failure of the yolk to be absorbed is the principal 
abnormal condition that is apparent. However, this condition is 
observed in very young chicks which have died through other causes, 
such as weak constitution, faulty incubation, and brooder defects. 
The liver usually shows an ochre color, with bands or streaks of 
congestion. This appearance is not constant as in some cases an 
apparently normal mahogany or chocolate colored liver is observed. 
In some instances the liver has the normal appearance, and the yolk 
sac has been absorbed. This is especially common in less acute 
cases. The lungs may show minute necrotic areas and, as a rule, 
congestion. 
Diagnosis. Diagnostic features of the disease are its early 
appearance, the high mortality within the first month, the occurrence 
of deaths within a few days after hatching, and the absence of inter- 
nal lesions other than unabsorbed yolk or striations on the surface of 
the liver. Confirmatory positive evidence is obtained by examina- 
tion of stained smears of the blood, liver or yolk with discovery of the 
causative organism. Further evidence is yielded by feeding or in- 
oculation experiments with young chicks. 
Artificial cultural methods are more precise. The causative or- 
ganism may be readily isolated in a pure culture from the heart 
blood, liver, spleen, kidneys or unabsorbed yolk. It may be differ- 
entiated from other organisms of a similar type by its cultural and 
biochemic characteristics, and by its agglutinating properties against 
a homologous serum. 
Differential diagnosis. Bacillary white diarrhea is differenti- 
‘ated from the other diseases commonly classed as white diarrhea by 
its early occurrence, the exceptional mortality, and the absence of 
the characteristic lesions of coccidiosis, or of aspergillosis. Coccidi- 
osis is slower in its development and usually affects chicks at a later 
period. It is manifested by hemorrhagic areas in the ceca, dilatation 
of these organs, and the presence of necrotic casts in their lumina. 
In the event that this disease is present, the coccidial cysts may be 
readily demonstrated on microscopic examination of the cecal con- 
tents. 
