174 LEACH. 



The mouth of the Leech is armed with a 

 sharp instrument that makes three wounds at 

 once, and may be compared to the body of 

 a pump ; and the tongue or fleshy nipple 

 to the sucker : by the working of this piece 

 of mechanism, the blood is made to rise up 

 to the conduit, which conveys it to the ani- 

 mal's stomach, which is a membranaceous 

 skin, divided into twenty-four cells. The 

 blood which is sucked out is there preserved 

 for several months, almost without coagulating, 

 and proves a store of provision to the animal. 

 The Leech will indicate the change of wea- 

 ther if confined in glass, agreeable to the 

 following experiment :- — 



Put a Leech into a large phial three 

 parts full of clear rain water, regularly 

 change the same thrice a week, and let it 

 stand on a window frame fronting the north. 

 In fair and frosty weather it will be motion- 

 less, and rolled up in a spiral form, at the 

 bottom of the glass ; but prior to rain or 

 snow, it will creep to the top, where, if the 

 rain will be heavy, and of some continuance, 

 it mil remain a considerable time ; if tri- 

 fling it will descend. Should the rain or 



