DISTOMATOSIS — LIVER FLUKE DISEASE — LIVEU ROT. 307 



larger quantities. The bad effects of wet seasons are not immediately 

 apparent, but appear during the following spring. 



Distomatosis is common throughout almost the whole of Europe, 

 Africa, and America. In France it is most serious in the moister 

 regions of Sologne, in Berry, the mountainous and wet districts of the 

 great central plateau, and particularly in the Pyrenees. It particularly 

 attacks oxen in the valley of the Meuse, the marshes of Picardy, the 

 lower regions of Normandy, and in aril the mountainous pastures of the 

 central plateau. 



Lesions. The lesions of distomatosis vary with the stage of develop- 

 ment of the parasites. During the primary phase of invasion of the 

 bile ducts by young distomata one finds interstitial diffuse hepatitis, due 

 to perforation of the gland by young parasites, adhesive perihepatitis, 

 with the formation of false membranes, and not uncommonly slight 

 peritonitis. 



Zoologists state that the young distomata penetrate the liver by 

 passing upwards against the current of bile. It does not appear impos- 

 sible, however, that they may penetrate by another path, particularly as 

 so-called "erratic" forms of distomatosis like distomatosis of the lung, 

 heart, lymphatic glands, and various other tissues are not uncommon. 

 It has been suggested that the young distomata, arriving in the bile 

 ducts, perforate the gland, giving rise to these lesions of perihepatitis, 

 peritonitis or erratic distomatosis ; but this view is scarcely in harmony 

 with the fact that the parasites are usually found in the bile ducts. 



During the second phase, corresponding to the development of almost 

 adult distomata, the perihepatitis and peritonitis set up either produce 

 fatal results by secondary infection or diminish and disapi^ear. The 

 parasites develop in the bile ducts, in which they attain the adult con- 

 dition. They steadily ascend towards the origins of the ducts, dilating 

 them in their passage in an extraordinary way. The number of para- 

 sites varies greatly : sometimes there are but few, and they are only 

 discovered on post-mortem examination ; in other cases the bile ducts are 

 crammed with them, as many as six or seven hundred or even a thousand 

 being present. The distended bile ducts always show chronic peripheral 

 inflammation, which steadily becomes aggravated, producing pericanali- 

 cular atrophying sclerosis. This condition is followed by change in and 

 disappearance of a certain quantity of hepatic tissue, and by various 

 forms of vascular and secretory disease. 



This is the period of greatest disturbance, not only in consequence of 

 the actual presence, but also of the mode of living, of the parasites. 



Moussu declares that the parasites live principally on blood, at least 

 during the first and second stage of their sojourn in the liver, adducing 

 as proof that if one completely injects the vascular system of the liver 



X 2 



