Scientific Intelligence. — Zoohgij, 888 



less is llie proportion of the consumption of oxygen to the pro- 

 duction of carbonic acid gas, whence a small quantity of atmo- 

 spheric air is respired for a moderate period. But when the re- 

 spiration is continued for a longer j^eriod in the same air, and 

 the strength of the individual begins to sink, the excretion of 

 the latter diminishes more rapidly than the absorption of the 

 former. We know that the higher classes of animals, when in- 

 closed in a certain quantity of air, die long before all its oxygen 

 has been exhausted. The case is very different with many of 

 the mollusca under the same circumstances ; for they not only 

 consume all the oxygen, but actually continue afterwards to ex- 

 pire carbonic acid gas ; consequently, after the respiration had 

 been continued for some time, there has been more of the latter 

 excreted than there has been consumed of the former; nay, 

 sometimes this occurs even before all the oxygen has been con- 

 sumed. — 3. The volume of the respired air generally remain* 

 unaltered. In some cases, where it was diminished, the portion 

 missing had evidently been swallowed; in others, it must have 

 been decomposed and absorbed. — 4. When the volume of air 

 remained unaltered (as it mostly did), there was always either 

 more or less oxygen consumed than carbonic acid produced. 

 The fact of the volume continuing the same under these cir- 

 cumstances, can only be accounted for by supposing the secre- 

 tion or absorption of some other gas, which could have been no 

 other than nitrogen. In some cases there was even far more 

 nitrogen than carbonic acid excreted. — 5. Insects transpire as 

 well as the higher orders of animals. In one experiment, an 

 humble bee lost in this manner the 17th part of its weight in 

 48 hours. — 6. From a comparison of these experiments with 

 those of others on the respiration of amphibia, fishes, and warm- 

 blooded animals, it appears that, while the cat breathes stronger 

 than the guinea-pig and the rabbit, and the dove stronger than 

 the cat; the bee, even at a temperature of I1J° R., produces 

 almost as much carbonic acid in proportion ; and at a tempera- 

 ture of 22° R. far more. A butterfly, even after having been 

 for some days without food, excretes a still greater quantity, at 

 a temperature of 15° R. Earth-worms and snails, at a tempe- 

 rature of ir to \T R., fall short of the warm-blooded animals 

 in this re&pect, but equal the toad, and exceed the tench. — 7. If 



