46 LUNG-FLUKES. 



which usually manifests itself about January. Diarrhoea and 

 jaundice occur now, and either death ensues or there is a spon- 

 taneous recovery. The last period is that of the emigration, 

 when the flukes are all mature and all the ova have been passed 

 out, the sheep then recovering. 



Generally, according to Neumann, flukes remain in their host 

 from nine to fifteen months. 



Effects on the liver. — When invaded the liver becomes thick 

 and soft, and the surface is rough instead of smooth. Inflam- 

 mation sets in, and a dark serous fluid is found in the abdomen. 

 The biliary canals become thickened and much enlarged. The 

 liver eventually becomes soft and friable. Flukes are of course 

 to be found in the diseased organs in numbers, the writer 

 having taken as many as seventy from one lamb's liver and 

 bile-duct. 



Liver-rot occurs worst in certain years. In Britain in 1816, 

 1817, 1830, 1853, and 1854 it was particularly bad, all wet 

 years. In 1830 England lost one and a half million sheep 

 from this pest, representing four millions of money. In 

 1879-80 three million died. In 1862 Ireland lost 60 per 

 cent of the sheep, and in 1882 millions died in Buenos Ayres. 

 Kecently the disease has been on the decline in Britain. This 

 Fluke occurs in many other animals, and man. 



Lung-flukes. — Sometimes flukes are found in the lungs of 

 sheep and oxen. These lung-flukes {D. pulmonale) are con- 

 tained in cysts, usually in the posterior lobe of the lung. The 

 cysts are ovoid in form, about the size of a walnut, and whitish- 

 grey in colour. Externally they are covered with a fibrous 

 capsule. Each cyst contains a fluid in which the fluke is 

 found. Found in dogs, cats, and man in China, Japan, and 

 Formosa. 



Another large Fluke, D. magnum, is found in deer, and 

 decimated the herds in the deer parks at Mandria, in Italy. 

 It seems to have been imported into America, and is now 

 almost as bad in the western plains as D. hepaficum. 



