29 



near the head and genital organs, which continued to 

 encrease from three to four hours under certain cir- 

 cumstances. The reason is evident : These animals 

 belong to the cold-blooded class, consequently the cir- 

 culation of the blood is very slow ; and the circulation 

 of the blood of animals, belonging to this class will 

 continue several hours after death — as the blood is not 

 so soon effected by the change produced on the body 

 by death, as on those animals belonging to the warm- 

 blooded class. 



We also know that the more perfect animals, when 

 killed by suffocation, that the blood always has a ten- 

 dency to stagnate about the parts essential to life ; the 

 same thing holds good in these humble creatures. 



The following conclusions may be drawn from the 

 preceding experiments. 



1. That the lumbricus terrestris has organs that 

 perform the office of respiration. 



2. That these worms consume nearly all the oxygen 

 of atmospheric air, and that it is necessary for their 

 vitality. 



3. That the carbonic acid gas which is formed, 

 when confined in the atmospheric air, is equal to the 

 quantity of oxygen consumed. 



4. That they live nearly as long again in oxygen 

 as in atmospheric air, and that the quantity of carbonic 



