$54 NATURALIST'S CABINET. 



Mode of its sucking blood. 



case and security, while it extends the other part 

 of the body in any direction ; and it is so firmly 

 fixed that it can move its head about to seek for 

 nourishment, without any danger of being carried 

 away by the strength of the current. When the 

 leech is desirous of moving onward, it extends its 

 body forward,, fixes its head in the same manner 

 that it did its tail, and then loosens and draws 

 that up, and again fastens it near its head as a 

 fresh point to proceed from. The head is armed 

 with three teeth of a slightly cartilaginous sub- 

 stance, which are so situated as to converge 

 when the animal bites, and leave a somewhat 

 triangular mark on the skin. These are suffici- 

 ently strong to pierce the skin of an ox or a 

 horse. Through the holes it forms with them it 

 sucks the blood: this is done by contracting the 

 muscles of the throat so as to make the blood 

 rush through the vacuum above the wound into 

 the stomach, which is a kind of membranaceous 

 receptacle divided into twenty-four small cells. 

 Here it sometimes remains for several months 

 almost without coagulating, and affords support 

 to the animal during the whole time. It passes 

 off by transpiration, the matter fixing on the sur- 

 face of the body, and afterward coming off in 

 small threads. In proof of this, if a leech be 

 immersed in oil (where it will keep alive for se- 

 veral days) and afterward put into water, a kind 

 of slough will be seen to loosen from its skin, 

 exactly of the shape of the body. When it is 



