in regard to Respiration. 259 



carbon exhaled from the animal, or- 1 should have obtained 

 this carbonic acid gas nearly in the same manner as when 

 the animals are shut up" in common airj and then it would 

 be proved that it did not depend on the oxygen of the air, 

 and consequently that it was exhaled immediately from the 

 bodies of these animals in an aeriform state, or in that of 

 carbonic acid combmed with caloric and become gaseous. 



I therefore shut up different kinds of worms just kill- 

 ed, in pure azotic gas extracted from the fibrous part, well 

 washed from the fresh blood by means of nitric acid, ac- 

 cording to the process of the celebrated chemist Berthol- 

 let; but in these experiments carbonic acid gas was mani- 

 fested. I confirmed this experiment by another, in which 

 I inclosed the animals in pure hydrogen gas ; and more than 

 once I had a quantity of carbonic acid gas produced in these 

 jnephitic gases, greater than when these animals were con- 

 fined in common air. I was therefore forced to conclude, 

 that the carbonic acid gas produced in these two cases was 

 no way dependent on the oxygen of the atmosphere; and, 

 consequently, that the oxygen gas destroyed by the presence 

 of these dead animals had its base absorbed by them. 



I remarked that several animals of this class could live 

 some hours in these mephitic gases. In consequence of this 

 obser\'ation I inclosed some of them, provided with organs 

 proper for respiration, in hydrogen and azotic gas; during 

 the same time I shut up other individuals of the same spe- 

 cies in common air. The result was, that in these two 

 cases I obtained nearly the same quantity of carbonic acid, 

 gas. In these animals, therefore, there was an absorption 

 of oxygen, and the appearance of carbonic acid gas was ei- 

 ther a production of carbonic acid gas, or of the carbonic 

 acid, the base of which escaped out of these animals. 



But it may, perhaps, be asked. Are worms the only ani- 

 mals which continue after death, or in their state of decom- 

 position, to absorb the oxygen of the atmosphere ? This 

 question appeared to me of so much importance that J en- 

 deavoured to solve it by experiments on other classes of ani- 

 mals superior to that of woims. I employed insects which 

 always retain the same form, as well as those which pass 

 through the three states of larva, chrysalis, and winged 

 beings. I made my experiments under all these circum- 

 stances. But after I had put to death these insects, and fol- 

 lowed their decomposition to the end, I always obtained a 

 complete absorption of oxygen when I left for some time 

 the putrefied matters shut up in common air : the absorp- 

 tioi* occasioned by the dead insects was, however, much 

 K 2 slower 



