318 INFECTIOUS ENTERO-HEPATITIS 
The liver affection in man appears usually as an abscess. In 
turkeys it appears as a variable number of foci in which the micro- 
parasites may be present in great numbers. The difference in the 
nature of the lesions must be largely attributed to the different reac- 
tion of the tissues of birds toward injuries. 
Hadley believed the cause to be a coccidium and states that the 
ameba described by Smith is identical with certain forms in the life 
eycle of the coccidium. His findings have not been confirmed. 
Symptoms. Diarrhea is the symptom which sooner or later may 
be expected to appear. It probably occupies the most prominent 
place among the objective manifestations. The disease of the ceca is 
presumably responsible for this. Diarrhea occurs with at least one 
other disease of the ceca and with the presence of tapeworms. Ema- 
ciation is pronounced in very chronic cases but it is not constantly 
present. As it may accompany other wasting diseases, it can not be 
depended upon as an indication of this affection. As the disease 
progresses the turkeys become less active, lag behind their flock or do 
not go out with it. Later the comb, wattles and even the skin of the 
head become dark colored, hence the popular name “‘blackhead.” 
The period of incubation is not known in the naturally infected 
turkeys. In those artificially infected by feeding lesions from diseased 
turkeys, the period is short until lesions appear in the ceca and liver. 
In Moore’s experiment with four turkeys fed on infected viscera, 
November 28 and the following days, two died of the disease Decem- 
ber 20 and 25 respectively. The other two were apparently well but 
upon examination one showed extensive lesions and the other was not 
affected. 
Morbid anatomy. Turkeys are attacked quite young. Smith 
found a turkey about three weeks old in which the disease had 
already made considerable progress. It seems, moreover, as if the 
disease is contracted only by the young, because in the examination 
of turkeys of different ages the oldest show lesions of the longest 
standing; that is, such as had undergone the most extensive trans- 
formation. In general it may be said that the age of the disease 
process corresponds with the age of the turkey. The most serious 
and extensive destruction of tissue occurs in the turkeys in the fall. 
In midsummer the disease is making most progress and the micro- 
parasites are present in greater numbers. It is probable that the 
