When the _eye_ is specially affected there are swelling of the lids, profuse lachrymation, closure of the lids by adhesion, and formation around their borders or on their inner surface and on the membrana nictitans of false membranes which press the lids outward more or less unevenly, and may be easily recognized when the lid is everted. The cornea and even the interior of the eye may suffer, leading to perforation, internal tension, and in some cases atrophy, with permanent blindness. The _tongue_ may suffer on the tip as in _pip_, or on its dorsum, from which the disease extends to the larynx, trachea and even the air sacks, which become filled with false membranes, that are coughed up, and decomposing in the mouth, add to the infection and fœtor. Dyspnœa and cyanosis of comb and wattles are marked features. The extension may take place downward along the alimentary track, the false membranes forming on the _gullet_ or _crop_ and interfering with swallowing or digestion, or on the intestine and determining a fœtid, often greenish or bloody diarrhœa with indications of false membranes. Vomiting may be a marked symptom. The _skin_ is usually attacked secondarily around the margin of the beak, the eyelids, the nares, the ears, the comb, the wattles, the anus, but it may develop at any point where the infecting material has touched an abraded surface. Trinchera found that in acute cases the acme was reached in fifteen days after which improvement might be looked for. A chronic form affecting the gullet might however persist indefinitely in pigeons without proving incompatible with good health. Paralysis of the wings or limbs may remain after the healing of the local lesions. _Mortality. Prognosis._ The disease is very fatal to both pigeons and chickens, 50, 70 or even 100 per cent. perishing when a flock is attacked for the first time. In flocks that have previously suffered, on the other hand, a large number are practically immune, and even if they contract the disease it assumes a mild form, and they survive but may retain the germ and continue to communicate it to others. Even the young of such immune flocks suffer less severely, coming as they probably do from less susceptible and therefore surviving birds, or having already perhaps contracted a mild (non-fatal) type of the disease from their parents.