_Treatment_ has been essentially local, consisting of swabbing with solution of boric acid (1:200), chlorate of potassa, perchloride of iron, or nitrate of silver. PSEUDOMEMBRANOUS STOMATITIS OF PIGEONS AND CHICKENS. Contagious and destructive nature of the disease. Mode of extension from the mouth and pharynx. Causes: bacillus diphtheriæ columbarum; its characters: pathogenesis to birds, mice, rabbits, Guinea pigs; dogs, rats, and cattle immune; diagnosis from bacillus diphtheriæ. American disease. Incubation. Symptoms: prostration; wheezing breathing; sneezing; difficult deglutition; false membrane on fauces; necrotic changes in mucosa; perforations; lesions of internal organs; blood infection; nostrils stuffed; bill gapes; lesions on eye, tongue, gullet, crop, intestine; diarrhœa; vomiting. Skin lesions. Course, acute, chronic. Paralysis. Mortality. Prognosis. Diagnosis from coccidiosis, from croupous angina of Rivolta, from aspergillus disease. Treatment: isolation; destruction of carcasses; hatching; destruction of dead wild birds and rabbits; exclusion of living; quarantine of new birds; disinfection; locally, antiseptics by inhalation, swabbing, and internally, iron in water. This affection prevails in certain countries and causes heavy losses among young pigeons, so that it might with great propriety be included among animal plagues, which should be dealt with by the State. The malady is a local inflammation leading to the formation of false membranes and its usual course is to progress from the mouth and pharynx, to the nasal passages, lachrymal ducts and sacs, the larynx, trachea, bronchia, intestines and skin. _Causes._ The essential cause of the disease is held by Löeffler to be the _bacillus dipththeriæ columbarum_, which is a short bacillus with rounded ends, a little longer than the bacillus of fowl cholera and not quite so broad. It is usually found in irregular clusters, especially in the interior of the hepatic capillaries. It is ærobic, non-motile, non-liquifying, and grows on nutrient gelatine, blood serum or potato. In gelatine it forms a white surface layer, and spherical colonies along the line of puncture, which show a yellowish brown tint under the microscope. On blood serum and potato it forms a grayish white layer. _Pathogenesis._ The bacillus is inoculable on other =pigeons= and as it usually appears in the young birds in the nest, still fed by the parent bird, it is probable that no inflammation nor abrasion is necessary to make it take. Pure cultures inoculated in the mouth gave rise to the usual local type of the disease. When inoculated subcutem it caused a local necrotic inflammation.