Jaundice, Icterus, the Yello7vs. 461 



plain the usually benignant course 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 (Stoedler, 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, 

 but is oxidized and decomposed in the blood so that it cannot be 

 detected, in blood or urine. But let the transformation be inter- 

 rupted, as in certain diseases of the lungs, with imperfect oxida- 

 tion, and the bile circulates in the blood, stains tissues and urine, 

 and in short causes jaundice. 



To sum up : it may be said that icterus is probably never due 

 to simple inactivity of the liver : it may, however, be caused by 

 excessive secretion of bile which is re-absorbed from obstructed 

 bile ducts or bowels : — it may result from imperfect transforma- 

 tion, in the blood, of the bile which is normally re-absorbed from 

 the intestine : or it may possibly be caused by the formation of 

 pigments in the blood from the abnormal transformation of bile 

 acids, or by solution of the haemoglobin of the blood corpuscles. 



The gravity of jaundice varies as much as its causes. It is 

 well known that the system may be saturated with bile, and the 

 tissues and urine deeply .stained without much con.stitutional 

 disorder. The pigment alone is not an active poison. But there 

 may be much attendant suffering from obstructed biliary ducts or 

 bowels, from diseases of the lungs, or from disintegration of the 

 blood globules and imperfect nutrition, or there may be profound 

 nervous prostration and disorder from uraemia, or from the pres- 

 ence in the blood of an excess of effete and partially oxidized 

 albuminoids (See Azotaemia). According to our present knowl- 

 edge, constitutional disorder, prostration and suffering in ca.ses of 

 jaundice, are mainly due to the presence in the circulation of these 

 albuminoids, and of taurocholic acid which latter has a most 

 destructive effect on the blood corpu.scles. 



The symptoms, therefore, are not characteristic apart from the 

 yellow coloration of the tissues and urine and the chemical 

 reactions of the bile acids and bile pigments furnished b}' the 

 latter. 



