122 DISEASES OF DOMESTICATED BIRDS 
The disease runs a rapid course in the former and deaths may 
follow in a few days. Older turkeys, fatally affected, usually suc- 
cumb within four weeks after the onset of symptoms. The mortality 
approaches 90 per cent in poults and 10 per cent or more in the 
grown birds, according to the extent of exposure. Affected poults 
exhibit a drowsy attitude with constantly increasing lack of vigor. 
They are unable to keep up with the flock in its daily travel over 
large areas. ‘The appetite is diminished, the feathers ruffled, wings 
are pendant, and a general air of debility is manifested. Diarrhea 
is nearly always present and quite characteristic. The droppings 
are soft and yellowish in color or may be mixed with brownish ex- 
crement. During the later stages the head may present a darkened 
or purple appearance due to impaired circulation of the blood. 
This symptom has led to the disease being termed “ blackhead.” 
However, this term is misleading since the darkened appearance 
of the head is not a constant symptom and may also be observed in 
other diseases which lead to a weakened heart action. In older 
turkeys the symptoms are less pronounced and may be of much 
longer duration. They show loss of appetite, unthrifty appearance, 
lessened activity, progressive emaciation and diarrhea, with soft 
yellowish droppings. The disease may persist for a period of two 
weeks to two months and result fatally or the bird may regain its 
normal condition. MRelapses frequently occur during the following 
year. The disease is more prevalent during the late summer or 
fall in young poults but may occur at any season and is frequently 
reported among grown turkeys during the winter and spring. 
Morbid anatomy. The lesions of entero-hepatitis are confined 
to the intestine and liver. In the intestinal tract the ceca are the 
principal seat of infection. In many cases only one cecum exhibits 
macroscopic alterations but quite frequently both ceca are equally 
involved. ‘The walls become greatly thickened and covered by a 
necrotic exudate which completely fills the cavity or leaves but a 
small central space. The accumulation of exudate gives rise to a 
marked distention of these blind pouches plainly apparent when 
the intestine is exposed at autopsy. The exudate is dull gray in 
color and of a friable or cheesy ‘consistency. The entire length of 
the cecum may be involved or only a limited area, depending on the 
severity or duration of the morbid process. In the majority of 
cases the liver is found infected to a greater or less degree. The 
lesicns are characteristic. Areas of degeneration appear on the sur- 
face in circular form and of varying size. They are usually about 
