384 Scientific In teWg ence. — Zoohgij. 



it always held good that the degree of animal heat varies as the 

 quantity of carbonic acid gas produced during respiration, the bo- 

 dies of bees and butterflies should be greatly heated when their 

 respiration becomes stronger ; however, it is not ; being the case 

 only when an inconsiderable quantity of nitrogen is produced at 

 the same time. The former has a less, and the latter a greater, 

 capacity for caloric than oxygen. Consequently, if a great 

 quantity of nitrogen is excreted along with carbonic acid, the 

 caloric that escapes at the development of the one, must be- 

 come latent again at that of the other. Now, insects often ex- 

 pire not merely as much, but even twice as much, nitrogen as 

 carbonic acid. — 8. From computing the weight of the carbonic 

 acid and nitrogen that is developed, and of the oxygen that is 

 consumed in a given time, and comparing that of the two for- 

 mer with that of the latter, we find that the weight of what is 

 taken in, exceeds that of what is given out ; but by so small a 

 quantity that the mass of the body cannot be sensibly increased 

 by it. The loss by transpiration, however, much more than 

 compensates for this, particularly in the higher classes of ani- 

 mals. — 9. This comparison of the loss and gain of ponderable 

 elements during respiration leads to another, and a very striking 

 result. In one of the experiments, a butterfly weighing two 

 grains, which had previously been upwards of three days with- 

 out food, gave out in 90 minutes 0.0078 gr. of carbonic acid 

 gas, which contained 0.00022 gr. of carbon. Now, supposing 

 it to have breathed in the same manner for the three preceding 

 days, it must have lost 0.1 gr. carbon ; but it had been breath- 

 ing so much stronger, that the loss may be estimated at least 

 0.15 gr. The hard parts of the insects could have had but little 

 share in this ; and as they weighed in another of the same size, 

 which had been well dried, 1.4 gr., the weight of the soft and 

 more vital parts can have been but 0.6 gr. However, allowing 

 it to have been 1 gr., the half of that at least was water, and 

 the remainder consisted chiefly of albumen, fibrine, and fat. 

 These may have contained about 60 per cent., that is 0.3 gr. 

 of carbon, while there were 0:15 gr. excreted ; consequently, 

 the soft parts had lost the half of their carbon. Notwithstand- 

 ing this, the butterfly was still so strong after the experiment, 

 that it could, probably, have lived for some days longer with- 



