478 Veterinary Medicine. 



the sequel of muco-enteritis affecting the duodenum, with swell- 

 ing of the walls of the common bile and pancreatic duct at its 

 orifice, or from obstruction by gall-stones, concretions, impacted 

 bowels or neoplasms. "With the arrest of the biliary flow the in- 

 testinal ferments gain an entrance into the common duct and the 

 sac of Vater, finding protection from the antiseptic bile in the re- 

 sulting catarrhal exudate, and in this way they reach the gall-blad- 

 der, the biliary radicles and the acini. With the entrance of bac- 

 teria or toxins by the portal vein on the other hand, there is first a 

 troubled condition of the acini and hepatic cells, an over-secretion 

 of thick bile, and blocking of the passages so that little is passed 

 into the intestine, the greater part being absorbed into the hepatic 

 veins. Fermentation microbes in the stomach and intestines, the 

 germs of suppuration and septicaemia, and saprophytic germs 

 from outside the body are held to be causative of icterus. Cadaec 

 lays much stress on the putrefactive germs in water, and traces 

 different attacks to marshes and foul ponds. 



As in other infecting diseases, early age has a predisposing in- 

 fluence. The older subject has presumably been already exposed 

 to the microbe and acquired some measure of immunity. Ani- 

 mals coming new to the locality and poison, are equally suscepti- 

 ble with the young. Trasbot found that 14 out of 17 dogs thus 

 attacked were between three and eighteen months. 



Leblanc and Trasbot claim mental shock as a cause of icterus 

 in the dog. The disappointment and weariness caused by the 

 master's absence, the excitement of a fiercely contested fight, and 

 brutal punishment are adduced as cases in point. Abuse of 

 emetics and purgatives, in connection with a preexisting hepatic 

 or duodenal disorder or as a supposed prophylactic of canine dis- 

 temper has induced jaundice. 



Obstruction of the small intestine has proved a factor, partly 

 by the reflex irritation through the splanchnic nerves, and partly 

 through obstruction to the common bile and pancreatic duct. 



Walley records a case of obstruction of the cystic duct by 

 extravasation of blood in the gall bladder. 



Icterus not infrequently supervenes during canine distemper in 

 which the early gastric and duodenal irritation becomes an occa- 

 sion of the extension of the catarrhal infection to the common 

 bile duct. Even apart from this, Trasbot has seen the majority 



