120 



ANIMAL PHYSIOLOGY. 



[LESSON 33. 



dense fleshy proboscis at 5, the central portion of the digestive tube, 

 which represents the stomach, at c; lateral, ccecal appendages at d, 

 and the vent at e. 



557. The Leech presents an interesting form of the mitrimental 

 organs ; the mouth is triangular, and armed with three Fig. 202. 

 crescentic jaws (a, a, Fig. 200), presenting their sharp 



convex margin toward the oral cavity, which margin 

 is beset with sixty small teeth (Fig. 201). 



It is by the action of these little saws upon the 

 tense integument seized by the labial sucker that the 

 triradiate bite of the leech is made ; the muscles of 

 the jaws are marked 5, b (Fig. 200). 



558. The oesophagus is short, and terminates in a 



FIG. 200. 



FIG. 201. 



Mouth of Leech. Jaw of Leech. Nutrimental organs, Leech. 



singularly complicated stomach, divided by deep constrictions into 

 eleven compartments, at the sides of which are coecal pouches, pro- 

 gressively though slightly increasing in length to the tenth, and dis- 

 proportionately elongated in the eleventh compartment (Fig. 202). 



559. Army Surgeons, who have required more leeches, after an 

 engagement, than they possessed, have availed themselves of the 

 knowledge of this peculiarity in the structure of the creature's ali- 

 mentary canal, to make one leech do the work of several, by simply 

 cutting off the lower part of the body, when the blood pours out in 

 a rush, emptying the canal immediately. 



Thereafter, the leech continues to suck blood, as long as he is 

 permitted to do so ; he always feels empty so his appetite continues 

 voracious. 



560. It is a common practice (in Europe), after a leech has left 

 a patient, to throw salt upon it, to produce vomiting, which it in- 

 variably does, but it kills the leech. 



561. The best plan is, to hold it firmly at the posterior portion 

 of the body with one hand, and draw it steadily through two fingers 



