The fact that animals suffering from distomatosis and slaughtered for food are well nourished is not a valid objection; for it has long been known that wasting and anæmia are not immediate consequences, and that before they are clearly apparent the distomata must have been present in the liver for several months. Bakewell and the Marquis of Behague have shown that in moderately infected animals there is a tendency to lay on flesh during the first and a portion of the second stage of development of the disease. If the animals are slaughtered before the period of progressive decline sets in, it is quite possible to form entirely wrong views regarding the importance of these parasites. The wasting process commences towards the end of the second phase of the disease, and then makes rapid progress. The parasites, which have then been continuously drawing on the blood for their nourishment for a long time, produce anæmia, and some infection of the bile ducts, and usually a certain degree of icterus. The third phase is accompanied by general signs of cachexia, which need not again be described. They are similar to those of all progressive cachexias. In animals which survive this phase and are ultimately slaughtered the liver always shows very marked sclerosis, commencing around the biliary ducts. Even after the parasites have been evacuated, these ducts appear indurated, thickened, fibrous, and sometimes encrusted with biliary deposits or obstructed with true calculi. These calculi may or may not contain parasites; sometimes they simply contain eggs: they are open, tubular, and perforated, but always irregular on the surface. When in addition complications have appeared, one usually finds general lesions of septicæmia and blood infection. In erratic distomatosis, which is of no importance clinically, distomata may become encysted in the lung or other viscus, and in time die. The cysts, which only contain one and rarely two parasites, present a fibrous shell, enclosing a blackish, pultaceous, grumous magma, which sometimes has undergone a certain amount of calcareous infiltration. The parasite may be entirely destroyed. =Diagnosis.= Early diagnosis is difficult, and can only be established by microscopic examination of the excreta and the discovery of eggs. On an average one may find one egg in each preparation when the liver contains 80 to 100 flukes. When wasting is very marked, and particularly when there has already been a number of deaths, diagnosis becomes extremely easy. It is sufficient to find flukes in any form (_Distoma hepaticum rel lanceolatum_) to be assured as to the cause of disease.