American Beaver ♂ (_Castor canadensis_) shows a slight bile obstruction and pigmentation through the liver but no pus or cirrhosis; bladder is collapsed containing only a little limpid brown fluid; wall is slightly roughened but not opaque; there is a blue- black stone 1.5 × 1 cm. free in the cavity; duct patulous; pancreas and intestine not affected. Brant Goose ♂ (_Branta bernicla glaucogastra_) liver shows slight fatty change; bladder much distended, contains twenty-six small, quite hard, greenish stones; one is impacted in the cystic duct which is not patulous. Pigtailed Macaque ♂ (_Macacus nemestrinus_) shows a normal liver; bladder contains a small black concrement, very hard, no cystitis. Polar Bear ♀ (_Ursus maritimus_) showed a chronic cholecystitis and cholangitis, the stone (?) in this case consisting of a solitary, black, friable mass, six mm. in diameter. Mongoose Lemur ♂ (_Lemur mongoz_) showed a normal liver; bladder of about normal size but the duct can be forced only by considerable pressure; there is a small stone and a granule in the tortuous cystic duct; no cholecystitis. The specimens that are preserved show these to be chiefly inspissated bile, those from the first beaver and the goose being the only ones to rise to the dignity of gall stones; it would seem that there was plenty of opportunity for calculi to form in the bladder of this beaver. In no case is there a cholangitis or cirrhosis dependent upon cholelithiasis. While stones have been shown as infrequent there is a condition of the bile which may be quite important. In Passeres, Accipitres, and Striges one frequently sees a very dense inspissation of the bile both in the cystic area and in the lesser independent bile duct. This need not be, indeed usually is not, associated with hepatitis or cholecystitis. There is no one thing more common than another in relation with it but the diagnoses most often made are enteritis, distention of the proventricle and gizzard, and constipation. INFLAMMATION OF THE BILIARY SYSTEM.