^22 Veterinary Medicine. 



composed of successive layers of nearly equal color and density 

 surrounding the central nucleus. They are on an average 

 smaller than the dark green variety but individual calculi have 

 been found of three ounces. 



The whitish or orange calculi are usually in the form of hollow 

 casts of the bile ducts having a dull white color externally and a 

 yellowish brown internally. They are usually thin, fragile and 

 crystalline and contain relatively more earthy salts than the two 

 first named varieties. From this cau.se also they have a higher 

 specific gravity.' One .specimen weighed 8 ounces. 



The biliary sand or pulp, is made up of granules of a yellowi.sh, 

 dark green or black color, forming with the bile a pultaceous 

 mass but drying into a consistent mass. It may be firmly adher- 

 ent to the muco.sa of the gall bladder and require to be scraped 

 off. These granules may be looked on as the first step in the 

 formation of calculi or encrustations. 



The causes of biliary calculi in cattle are mainly close confine- 

 ment, dry feeding, abundant rations, the presence of trematodes 

 in the bile ducts and finally microbian infection. 



Lesions vary. With obstruction of the common bile duct or 

 cystic duct, there are usually dilatation of the bile ducts with 

 fibrous thickening of their walls so that they .stand out as white 

 branching lines on the back of the liver. In extreme cases the 

 common duct may acquire the calibre of the small intestine. The 

 gall bladder may participate in this thickening (Chassaing) or 

 may even rupture (Proger, Shaw). 



In connection with ob.struction microbian infection extends 

 upward into the liver, and in rupture of the bladder an acute, 

 diffuse septic peritonitis follows (Chassaing). This only follows 

 on infective inflammation of the gall bladder. Aseptic bile causes 

 little or no irritation. 



Symptoms. As in the horse, general symptoms of ill health or 

 hepatic disorder are not pathognomonic. The presence of inter- 

 mittent attacks of constipation, and colic, with icterus, tympanies 

 and violent efforts at expulsion are the diagnostic symptoms of 

 an acute attack. Pulsation and respiration are accelerated, and 

 the urine dense, high colored, oily and slightly yellow. Reboul 

 has noticed that symptoms are aggravated on exposure to cold ; 

 there are great prostration and dullness, frequent moaning and 



