THE OX AND THE DAIRY. 207 



struction to the passage of the bile through the ducts, either 

 from alteration of the intimate structure of the liver, or from 

 the pressure of tubercles or tumours 



There is, however, another and very common cause of 

 jaundice, which in noticing the morbid affections of the liver 

 we cannot here omit to describe ; we allude to the obstruction 

 of the biliary ducts by gall-stones. It is astonishing how 

 often gall-stones are found in the gall-bladders of cattle : they 

 vary in size from a pin's head to a walnut, and as long as 

 they cause no obstruction, they neither inconvenience the 

 animals nor interfere with health. But sometimes, nay very 

 often, they enter the duct which conveys the bile to the in- 

 testines (the cystic duct) from the gall-bladder, which unites 

 with a larger common duct from the liver itself, before enter- 

 ing the duodenum. When a gall-stone enters the cystic duct, 

 it soon becomes impacted ; it stops the current of the bile ; 

 spasmodic action of the muscular fibres of the duct, occa- 

 sioned by the irritation, and accompanied by violent agony, 

 succeeds ; the skin and eyes become suffused with bile; gene- 

 rally in due time (longer or shorter according to the size of 

 the stone or calculus) the duct is dilated, and the obstructing 

 object passes into the larger common duct, along which, not 

 however without causing some obstruction, it proceeds till 

 it comes to its entrance into the intestine (duodenum). Here 

 again it meets with a fresh difficulty ; this entrance is sur- 

 rounded by muscular fibres, which act as a sort of valve, or 

 rather as a constriction, yielding freely to the pure bile, but 

 contracting on the irritation of a preternatural object. Before 

 this barrier is forced, spasmodic agony again takes place ; at 

 length the muscular fibres yield, and the gall-stone passes 

 into the intestine ; the pain ceases, but it is some time before 

 the jaundice of the skin disappears. Unfortunately, when 

 this occurrence has once taken place, it opens the way for 

 repetitions of the whole affair, and calculi sometimes lodge 

 in the ducts for a considerable time, producing confirmed 

 jaundice. This state of things cannot exist without produc- 

 ing general derangement of the system ; the alimentary canal 

 is immediately affected ; loss of appetite, constipation, thirst, 

 a hard quick pulse, a heaving of the flanks from increased 

 and febrile respiration, dulness, and loss of strength and 

 flesh, with yellowness of the skin, of the eyes, and of every 

 secretion, milk, urine, &c., are prominent symptoms. The 

 skin becomes dry, and throws off yellow mangy scurf, and 



