21 



SECTION III. 



TO ascertain the effects produced on atmosphe. 

 ric and oxygen airs, by these animals, I perforraed all 

 the experiments over mercury, to prevent the absorp- 

 tion of the carbonic acid gas, if any there should be, 

 produced by the supposed respiration of the animals. 



EXPERIMENT I. 



I filled a glass vessel with mercury, and inverted 

 it on the shelf of the pneumatic apparatus, and trans- 

 mitted into it two measures of atmospheric air, previ- 

 ously washed in lime water ; into which was intro- 

 duced four worms, washed and wiped perfectly dry. 

 There was placed under them a small circular piece 

 of wood, by which they were separated from the mer- 

 cury during the experiment, which might have proved 

 injurious to them. The piece of wood employed was 

 less in diameter than the vessel. They lived in this 

 situation fifty-four hours ; and were then removed by 

 a piece of wire bent at one extremity. The next thing 

 to be done was to ascertain what change had been pro- 

 duced on the air in which the worms had been confin- 

 ed. After having filled an eudiometer with lime 

 water, and introduced into it a measure of the air, cor- 

 responding to the graduated portion of the instrument; 

 by agitating it, the water rose 12 degrees: consequently 



