708 Jounial of Agriculture, Victoria. [10 Dec, 1917. 



The ajjpearaiices in tlio liver vary so iiiiicli according to the presumed 

 method of infection that it will be better to describe the lesions under 

 two headings. 



(1) Ordinary Appearance of Livers Affected witii FIul<e. 



In this it would appear most probable that infection has been by 

 way of the bile duct. The presence of flukes in the bile ducts causes a 

 chronic inflammatory condition resulting in marked enlargement of the 

 ducts, and, at the .same time, great thickening of their walls. The left 

 lobe is frequently more seriously affected than the right, and very com- 

 . monly the left lobe alone is found affected. 



The affected part of the organ usually appears shrunken, and the 

 surface is often irregular, due to the presence beneath the capsule of the 

 thickened bile ducts, which may be felt as hard cords, ana which give 

 rise to the term " pipy " liver. 



On cutting into the organ the great changes in the bile ducts may be 

 readily observed. They are dilated, and their walls thickened with 

 white fibrous tissue. The lining membrane of the ducts may be red and 

 inflamed, but more often it is dark in colour and is sometimes calcified. 

 The bile ducts contain brownish, glairy fluid, flukes and their eggs. 



Xot only is there an increase of fibrous tissue around the larger ducts, 

 but also around the smaller, even down to the smallest, which makes 

 affected portions of the liver paler and harder than normal. 



(2) Type of the Disease whicii has been so prevalent during 



the past Year. 



In this, a.s mentioned before, infection seems to have been by way of 

 the blood. These ca.ses are acute — not chronic like the ordinary type 

 of fluke disease. In the great majority of them the whole liver is 

 affected, and on this account, and also owing to the fact that the para- 

 sites are in the blood vessels and occasionally in the actual secreting tissue 

 of the liver, this type of the disease is much more serious. The flukes 

 found in such cases are never very large — sometimes, in fact, they are 

 only with great diftienlty discovered with the naked eye. At the same 

 time, they are often very numerous, and produce much irritation, as is 

 evidenced by the greatly altered appearance of the liver and by the 

 fact that the condition so often causes death of the animal. 



The liver, in these cases, is best described as mottled, there being 

 greyish, yellowish, greenish, and blood-red areas thickly scattered 

 through it, while the capsule or covering of the liver is somewhat 

 thickened and roughened. There is not, in the early stages, any marked 

 fibrous condition of the organ, and the bile duets do not stand out pro- 

 minently as in the common chronic form. A few very small flukes may 

 be squeezed out on pressing a cut surface. These are usually mixed with 

 a quantity of reddish pus-like material, and lie in irregular cavities in 

 the organ". Microscopically, we find that the chief changes are in the 

 vessels (portal veins) and in the secreting liver tissue, to which latter 

 the parasites often escape from the vessels. The majority of these para- 

 sites are iisuallv dead, but even in that state produce a considerable 

 amount of inflammation. The blood vessels of the liver, as is to be 

 expected, show inflammatory changes, which, interfering with their 

 function, iiroduce serious effects on the liver tissue. 



