20G LECTURE V. 



seum in the common earth-worm. The 

 animals of this class have in general large 

 vessels on each side Iving in contact with 

 the air-vesicles or lungs, which are consi- 

 dered as the venous trunks returning the 

 blood to the dorsal vessel. They are exhi- 

 bited in the Museum injected in the leech. 

 Mr. Hunter says, " they are the venas cavas, 

 or great returning veins of the body, and 

 also the pulmonary veins ; for in them the 

 blood is aerated." His mode of expressing 

 this two-fold office, is by saying, " such veins 

 are both corporeal and pulmonary." 



It must be exceedingly difficult to inject 

 the vessels of vermes, so as to display their 

 communications; nor do I find that Mr, 

 Hunter has made any preparations to de- 

 monstrate the various branches of the dor- 

 sal vessel or its returning veins. What is 

 asserted in general with respect to this sub- 

 ject, has, I believe, been chiefly discovered 

 by observations made with the miscroscope 

 on those animals when living. Mr. Hun- 

 ter, in expressing his observations on the 

 manner in which the body is supplied 



