470 Veterinary Medicine. 



hepatic capillaries as when the aorta is mechanically compressed 

 by abscess, neoplasm, ingesta, or otherwise, just behind the dia- 

 phragm (Heidenham, Brunton). The cause is the same in both 

 cases, namely, the want or balance between the fullness and 

 tension of the bile ducts, and the hepatic blood vessels. There is 

 increased fullness of the hepatic biliary ducts, or decreased 

 plentitude of the hepatic capillaries and lymphatics. 



It must be added, however, that the coloring matter of the bile 

 is apparently produced, in the liver,, from that of the blood, and 

 that the pigment (hsematoidin) , found in old extravasations of 

 blood, is probably identical with bilirubin, and that any agent 

 or condition which causes liberation of the coloring matter of the 

 red blood globules, will cause a staining of the tissues, like that 

 of jaundice. The following agents are known to have this 

 effect on the blood globules : water, in hydrosemic states of the 

 blood (Hermann) ; taurocholate of soda from absorption of bile 

 (Frerichs, Kiihne, Feltz, Ritter) : chloroform (Chaumont) ; 

 ether (Burdon-Sanderson) ; freezing (Rollet) ; a high tempera- 

 ture+6o° C. (Schultze) ; frictional aud induction currents of 

 electricity (Burdon-Sanderson) ; the alkalies (ammonia, potass 

 and soda) and nitrites when present in excess. 



The injection of haemoglobin into the veins of dogs has been 

 followed by the appearance of bile pigment in the urine, but 

 Naumyn, Wolff, Legg and Brunton failed to obtain the same 

 result in rabbits. 



It is noticeable that the haemoglobin of horses' blood is very 

 soluble at all temperatures and that of dogs very slightly so 

 (Burdon-Sanderson). This may serve to explain the great, pre- 

 valence among solipeds of diseases, associated with dusky brown 

 or yellow discoloration of the mucosae, with petechise, and with 

 the passage of blood pigments in the urine. It may further ex- 

 plain the usually benignant conrse of jaundice in the horse and 

 its extreme gravity in the dog. 



There is further reason to believe that the bile acids, when in 

 excess, may be transformed into bile pigment in certain conditions 

 of the blood, as occurs under the action of sulphuric acid out of 

 the body (Stcedler, Meukomen, Folwarcyny, Rohrig). Moreover, 

 in the healthy state, the greater part of the bile secreted, includ- 

 ing acids and pigment, is re-absorbed from the intestinal canal, 



