106 BOAED OF AGRICULTUEE. 



It is chieflj found in the gall-bladder and bile ducts, but 

 occurs also in the intestine, and sometimes in blood vessels. 

 In the human subject it has, in some instances, been found in 

 tumors beneath the skin. In these cases it is supposed that 

 the larvae entered from the exterior by boring through the 

 skin. 



Effects. 



The injurious effect of this parasite is best known in the 

 case of sheep. In these animals it produces the fatal disease 

 generally known as " rot,"* " water-rot," or " fluke-rot." In 

 severe cases of this disease there are always large numbers of 

 flukes in the bile-ducts and gall-bladder, — often several dozens 

 and sometimes several hundreds, or even a thousand in some 

 fatal cases. A few may exist in a sheep without causing any 

 marked disease ; in proportion to the number, the symptoms 

 become more marked and the disease more fatal. In some 

 wet seasons, and in certain districts, these parasites have 

 destroyed immense numbers of sheep. Thus in 1830-1 it is 

 estimated that between one and two million sheep died of 

 this disease in Great Britain. If the number was but 1,500,- 

 000, it would represent a loss equal to about $20,000,000. In 

 a single year, in England, individual farmers have lost from 

 300 to 800 sheep in the same way. In France, during the 

 year 1812, according to Davaine, 300,000 sheep died by the 

 same cause in the vicinity of Aries, and 90,000 at Nimes 

 and Montpellier. In Germany, Holland, and most other 

 European countries similar disastrous outbreaks of the dis- 

 ease have occurred every few years, while during the most 

 favorable years the aggregate annual loss is far greater than 

 is generally supposed. In this country there are no reliable 

 statistics by which the losses from this cause can be estimated. 

 Yet there can be no doubt but that it amounts in reality to a 

 large sum annually. Even those sheep that have the disease 

 in a milder form and are sent to the market before they be- 

 come too sick to be moved, lose very much in value, and are 



*This must not be confounded with an entirely different disease, known as 

 " foot-rot." 



