68 PLATYHELMINTHES TREMATODA CHAP. 



The symptoms of " rot " appear about a month after infection, 

 more acutely in lambs than in sheep, and again, less in oxen than 

 in sheep. At first, death may result from cerebral apoplexy, but 

 if the first few weeks are passed through, a pernicious anaemia 

 sets in, the sheep are less lively and fall at a slight touch, the 

 appetite diminishes, and rumination becomes irregular. The 

 conjunctiva is of a whitish-yellow colour, the dry, brittle wool 

 falls off, and there is sometimes fever and quickened respiration. 

 In January, about three months after infection, the wasting, or 

 fatal, period sets in. Oedemas or swellings, usually visible before, 

 become larger at the dependent parts of the body, a large one in 

 the submaxillary region being especially well marked, and this 

 is considered one of the most characteristic symptoms (" watery 

 poke "). Through this period few of the infected sheep survive, 

 but should they do so, the flukes begin to migrate, though some 

 remain much longer within the liver. Migration is effected 

 through the bile-duct into the duodenum and outwith the faeces, 

 in which the altered remains of the Distomum are sometimes 

 scarcely recognisable. Under these circumstances (or owing to 

 death of the fluke in situ') the sheep recover more or less fully. 



The preventive measures seem to be: (1) Destruction of the 

 eggs and of the manure of rotten sheep ; (2) slaughter of badly 

 fluked sheep ; (3) adequate drainage of pastures ; (4) an allowance 

 of salt and a little dry food to the sheep ; and (5) dressings of 

 lime or salt on the ground to destroy the embryos. 1 



Distomum hepaticum, contrary to most Trematodes, enjoys a 

 wide range of hosts. Man himself occasionally falls a victim ; thus 

 in Dalmatia, in the Narenta Valley, the disease is endemic but 

 slight in its effects. The horse, deer, camel, antelopes, goat, 

 pig, rabbit, kangaroo, beaver, and squirrel have all been known 

 to harbour this fluke occasionally. In the Italian deer-parks at 

 Mandria a large species, D. magnum, decimated the herds some 

 years ago ; and this species, probably imported from Italy, is now 

 almost as dangerous a parasite on the western plains of the 

 United States as D. hepaticum. 



Bilharzia haematobia? This formidable parasite was dis- 

 covered by Bilharz in 1853 in the veins of the bladder of patients 



1 See Thomas, Quart. Jo-urn, Micros. Science, xxiii. 1883. Neumann, Parasites 

 of Domesticated Animals, translated by Fleming, 1892. 



- Leuckart, loc. cit. ; Looss, Archivf. mikroskop. Anatomie, Bd. xlvi. 1895, p. 1. 



