108 CLASS ANNULA.TA. 



which it is found. In Winter the leech retires to waters 

 of considerable depth, and seeks shelter in the mud at 

 the bottom ; but in the Summer it appears to delight in 

 shallow pools, basking, as it were, in the warmth of the 

 sun : but if the water it frequents is in danger of being 

 dried up by the Summer-heat, the leech buries itself in 

 the mud at a considerable depth. Just before a thunder- 

 orm, leeches appear much agitated, and rise frequently 

 to the surface of the water ; this, therefore, is considered 

 by the leech-gatherers as a favourable time for collecting 

 them. 



The property by which a leech anticipates thunder, 

 has induced some persons to employ it as a species of 

 barometer ; for this purpose a leech is enclosed in a 

 glass vessel half-filled with water, and the following is 

 supposed to be the result. When the weather is about 

 to be serene and pleasant, the leech will remain at the 

 bottom of the vessel without the least movement ; se- 

 condly, if it is about to rain, the animal will rise to the 

 surface, and there remain until the approach of fine 

 weather; thirdly, before boisterous weather, it will 

 appear in a state of great agitation ; fourthly, on the 

 approach of thunder, it will remain out of water for 

 several days, appearing agitated and restless, and so on. 



This natural barometer appears to answer tolerably 

 well, if there is sufficient belief in its virtues on the part 

 of the possessor, and if one leech only is employed; but 

 when several of these creatures are enclosed in the same 

 vessel, they do not appear to obey the same laws, and, 

 consequently, their movements do not correspond with 

 sufficient accuracy to render their indications of the 

 weather of much use. 



The medicinal leech appears during its whole Ufe to 



