INTRODUCTION. 



THE respiration of animals has long been a 

 difficult problem in physiology, and must have still 

 remained so had chemistry continued in an unculti- 

 vated state. Within these last few years this science 

 has been much improved, and has been applied to the 

 respiration of the more perfect animals with great 

 satisfection. 



Spallanzani has applied it to a number of beings 

 holding a low station in the great genus of animals- 

 such as several species of the snail : My object is to 

 descend a link or two lower, and ascertain whether it 

 is applicable to the common earth worm. 



To avoid the danger of being misled by inaccurate 

 observation, the experiments were repeated several 



