162 PHOSPHORESCENCE. L.ECT. VIII. 



three glasses ; in all the volume of gas had diminished, and 

 certainly on account of the formation of carbonic acid, 

 which was afterwards absorbed either by the humidity of 

 the insects, or by the film of water which covered the mer- 

 cury. Thus, in the first, the gas was 6-2 cubic centira.; in 

 the second, 5*4 cubic centim.; in the third, the volume had 

 not sensibly lessened. The entire insects were yet alive, 

 and glowing ; the segments were equally phosphorescent ; 

 and the mutilated or halved insects moved. In the first 

 glass, after the absorption effected by potash, there re- 

 mained 3'8 cubic centim. of oxygen ; in the second, 3'7 

 cubic centim.; in the third, 8-2 cubic centim. The potash 

 had consequently absorbed 2-8 cubic centim. of the carbonic 

 acid produced by the entire insect ; 1*9 cubic centim. of the 

 carbonic acid proceeding from the insects deprived of the 

 segments ; and 0-8 cubic centim. of the acid yielded by 

 the phosphorescent substance alone. In examining these 

 numbers, it is curious to find that the two parts, into which 

 the animal had been divided, should act separately with 

 the same degree of intensity, as in the entire insect, as if 

 they possessed a life in common.* 



I have repeated the experiment several times, and have 

 always found, that the absorption effected by the entire in- 

 sect surpassed, by a much larger quantity than the numbers 

 cited, the amount of absorption of the demi-glow-worms and 

 their luminous segments. I will relate another experiment, 

 which led to the same results as the preceding. I intro- 

 duced several glow-worms into a bell-glass, filled with 



* The reader will perceive that, while twenty entire glow-worms pro- 

 duced 2-8 cubic centimetres of carbonic acid, the separated parts of twenty 

 other animals producad only 2-7 cubic centimetres (1-9 -{- 0-8) of this^gas. 

 The difference, therefore, is (M of a cubic centimetre, and is probably 

 referable to the absorption of a portion of the gas by moisture on the por- 

 tions of the mutilated animals. J. P. 



