BLACKHEAD IN CHICKENS AND ITS EXPERIMENTAL PRODUCTION BY FEEDING EMBRYONATED EGGS OF HETERAKIS PAPILLOSA.

Feeding embryonated eggs of Heterakis papillosa to brooder chickens led to a disease of both ceca, characterized by the presence of a core consisting of fecal matter, coagulated blood, and emigrated cells from the mucosa. The walls of the ceca were thickened as a result of cell invasion and multiplication, invasion and multiplication of Amoeba meleagridis or allied parasites, and more rarely hemorrhage and edema. The respective parts played by Heterakis papillosa and the protozoa in starting the lesions and the source of the protozoa remain to be defined. The invasion of the liver by the protozoa was insignificant.