C ^79 ] 



branches, anfwcrlng to thofe of the Vena Porta in 

 the human body, the feccrning vcfTels are too mi- 

 nute to admit the impregnated ova, which, adhe- 

 ring to the membrane, produce thofe animaJculae 

 that feed upon the liver and deftroy the fheep. 

 They much refcmble the flat fifh called plaice, are 

 fometimes as large as a filver two-pence, and are 

 found both in the liver, and in the pipe (anfwering 

 to that of the vena cava) which conveys the blood 

 from the liver to the heart. 



If the form of this animal be unlike any thing 

 we meet with among the infedl tribe, we fhould 

 confider that it may be fo fmall in its natural flate 

 as to efcape our oblervation. Or might not its 

 form have changed with the fituation ? ** The ca- 

 " terpillar undergoes feveral changes before it pro- 

 " duces a butterfly." 



The various accounts which every diligent en- 

 quirer mud have met with (as well as the indefa- 

 tigable Mr. Young) feem very confident with the 

 theory of this difordcr. 



If dry limed land in Derbyfhire will rot in com- 

 mon with water-meadows, and ftagnant marfhes; 

 if fome fpringy lands rot when others are perfedlly 

 fafe; — is it owing to the circumftance of water, 



or 



