Causes: microbes, diagnosis from fowl cholera, less virulent rapid and deadly, and comparatively harmless to the rabbit, debility, youth, age, unsuitable food, ill health: bacillus gallinorum, bacillus coli communis, bacillus of duck cholera, spirillum Metchnikowi. Symptoms: dullness, fever, langor, inappetence, thirst, pale comb, greenish fæces, erect plumage, drooping wings and tail, sunken head, gaping, staggering, somnolence, bloody fæces, violet comb, low temperature, death in one to three weeks. Diagnosis: by restriction to one flock, or species, and immunity of rabbits. Mortality 80%. Prevention: separation of sick and healthy, disinfection of roosts and yards, pure food and water boiled or acidified, immunization. Treatment: boiled food with antiseptics, antiseptic enemata, stimulants, tonics. _Causes._ A number of different microbes are implicated in producing and maintaining catarrhal enteritis in the domestic poultry. All forms of the disease are therefore closely related to the well known fowl cholera, which is however to be differentiated, by its more intense virulence, rapid progress, and its deadly effect when inoculated on the rabbit. As in other forms of microbian enteritis, that of fowls is undoubtedly favored by general and local debility, youth, old age, unsuitable food and other health depressing causes, yet as the specific pathogenic microbe has been in many cases identified, it is well to consider some of the different species. =Bacillus gallinorum= found by Klein (1889) in the blood of chickens suffering from an infective diarrhœal enteritis, is ovoid, with rounded ends, from 0.8 to 2_μ_ long and 0.3 to 0.4_μ_ thick; often in pairs. Stains in the aniline colors. Ærobic (facultative anærobic) non-liquifying, non-motile, asporogenous. Culture easy in neutral, alkaline or slightly acid media at room temperature, or better in thermostat. On gelatine plate films, it forms grayish white, superficial colonies, becoming flat homogeneous white discs, brownish under transmitted light. The deeper colonies are small spherical and brown or yellowish by transmitted light. On agar it forms a thin gray layer with irregular margins, which extends over the entire surface. In bouillon it causes turbidity and in 24 hours a precipitate of bacilli to the bottom. =Pathogenesis.= Chickens inoculated hypodermically or intravenously die in 1 to 5 or 6 days with peritonitis and intense intestinal congestion. Fed in vegetable food it is harmless, but with animal food virulent. Rabbits and pigeons are immune. Pond water is a common source of casual infection, also dung heaps in which carcasses of little chicks have been buried. Summer is the period of greatest prevalence, as there is the best opportunity for the multiplication of the germ, and the drying of the ponds concentrates the product.