468 Veterinary Mediciiie. 



direct microbial! infection, and of poisoning by ptomaines and 

 toxins generated out of the body. Exposure manifestly has 

 something to do with the prevalence of canine icterus, which is 

 more common in spring and especially in autumn than at other 

 seasons. In hunting dogs, out of condition, the suddenly in- 

 duced over-exertion and fatigue, and the succeeding chill in cold 

 air or water, become accessory factors. 



It appears to be most commonly the result of the transference 

 of germs from the intestine, either by way of the bile ducts, or 

 with the blood through the portal vein. The first form is usually 

 the sequel of muco-enteritis affecting tlie 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 intes- 

 tinal ferments gain an entrance into the common duct and the .sac 

 of Vater, finding protection from the antiseptic bile in the result- 

 ing catarrhal exudate, and in this way they reach the gall-bladder, 

 the biliary radicles and the acini. With the entrance of bacteria 

 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 pas.sed 

 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. Cadeac 

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

 different attacks to marshes and foul ponds. 



As in other infecting diseases, earl}' 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. 



lycblanc and Trasbot claim mental shock as a cause of icterus 

 in the dog. The disappointment and wearine.ss 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 cotniection with a preexisting hepatic 

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

 temper has induced jaundice. 



