“During the past winter, I have made several observations upon the changes which follow ligature of the bile ducts in animals. The animals used were cats; these seem to survive the operation better than dogs. Most observers find that dogs live only five to ten days after. The way in which the ligature was applied was as follows:--The animal was first secured in a Czermak’s holder, and chloroform given largely, so as to secure a deep narcosis.… A cut is then made through the linea alba from the xiphoid cartilage downwards for about two inches.… Pushing aside to the left the stomach and duodenum, and raising the free edge of the liver, the bile ducts are seen coming from the liver and gall bladder.… A ligature is then put around the common duct and tied close to the duodenum; another is tied tightly on the duct, about half an inch nearer to the liver, and the duct between the two ligatures divided by a pair of scissors, the vessel being held out from the portal vein for that purpose. In two of the cats the bile found its way again into the intestine; in the later operations, therefore, I removed altogether about half an inch of the common duct as is done in making biliary fistulæ. The belly walls were then brought together with ordinary sutures. It is well to place these close together, as I lost three of the cats from the giving way of the sutures and consequent prolapse of the bowels. All the operations recorded in this paper were done in the pharmacological laboratory of my friend and colleague, Dr. Brunton.… “Exper. I., Jan. 24, 1873.--Large tabby cat, weighing 8½ lb.; very fat; bile ducts tied double and cut. The cat died probably on Jan. 26. Examined on Jan. 27. Weather frosty.… “Exper. II., Jan. 24, 1873.--Black she cat, weighing 6 lb. 6¾ oz. Bile duct tied double but not cut. Animal pregnant. The cat died on Jan. 26. Examined on Jan. 28.… “Exper. III., Feb. 3, 1873.--Large tabby cat, weighing immediately after operation 7 lb. 3½ oz. Animal very fat; bile duct tied, but not cut. Feb. 6.--Cat seems to be dying; it is unable to stand, but lies on side mewing. Feb. 7.--Found dead at 11 a.m. in the same place where left yesterday.… “Exper. VI., Feb. 3.--A cat not fully grown, very wild, scarcely any fat on body, weighing immediately after the operation 3 lb. 5 oz. Bile ducts tied double, but not cut. The animal nearly died under the chloroform, but recovered with artificial respiration. Cat last seen alive on Feb. 7.… Found dead on morning of February 12, and already much decomposed. Cause of death, prolapse of bowels.…