372 



RESPIRATION. 



Regnault and Reiset, as well as myself, have experimented on 

 the respiration of insects, as had been previously done by 

 Spallanzani, Saissy, and Treviranus. 



Reiset and Regnault employed cockchafers and the caterpillars 

 of the silkworm when near the time of spinning, for their experi- 

 ments on the respiration of insects. Their results were as 

 follows : 



In my own experiments on the excretion of carbonic acid in 

 insects, I obtained* the following results for 1000 grammes' weight 

 of the animals for one hour : 



The respiration of animals breathing through gills, as fishes,, 

 crustaceans, &c., differs from that of creatures breathing through 

 lungs or tracheae, inasmuch as already dissolved oxygen is conveyed 

 to the blood or the nutrient fluid, from which the dissolved 

 carbonic acid must be removed. The mechanism by which the 

 oxygenated water is propelled to the gills, and that which is 

 loaded with carbonic acid is again removed, is so complicated, that 

 mere indications of its character would carry us beyond our limits. 

 There have unfortunately been but few experiments instituted with 



* Op. cit., p. 42. 



