EXPEEIMENTS OF EEGNAULT AND EEISET. 171 



ting this motion. The result of this was that a portion of the air of the 

 bell was alternately drawn into each of the cylindric vessels, its carbon- 

 ic acid removed by the potash, and then it was returned ; so, as fast as 

 the animal produced that gas by breathing, the potash removed it, giving 

 rise, therefore, to a tendency to a certain amount of rarefaction in the air 

 of the bell ; but, 3d, on the opposite side of the bell were placed three 

 receptacles, e, e', e", filled with pure oxygen gas, which flowed into the 

 bell through the tubes fh, fh, f'h, to compensate for that rarefaction, 

 coming in by a bubble at a time through the little potash flask i, the 

 oxygen being pressed out of the reservoirs by a solution of chloride of 

 calcium descending through a stop-cock, c, from a reservoir, b b', kept at 

 a constant level in the usual manner by the flasks a, a', a". As fast as 

 one receptacle was exhausted, the pressure tube was successively con- 

 nected with the others, and so the supply kept up. Attached to the 

 stand supporting the animal was a eudiometer, o, which enabled a small 

 quantity of air to be withdrawn from the bell at any moment for the 

 purpose of analytical examination. For other details of this apparatus, 

 and the particulars of its method of use, reference may be made to the 

 original memoir itself. It is sufficient for the present purpose to under- 

 stand that an animal could be kept in the interior of this bell for several 

 days without showing any signs of discomfort, pure oxygen being sup- 

 plied to it, and the carbonic acid produced by breathing removed by the 

 play of the machine itself. 



The following is an abstract of the results obtained : 



1st. Hot-blooded animals, mammalia and birds, under their ordinary 

 diet, always disengage a little nitrogen by respiration, the Hot blooded 

 amount varying from less than y-J-^- to jfe of the weight of animals on an 

 the oxygen they consume. 



2d. When these animals are fasting, they often absorb nitrogen in pro- 

 portions similar to the preceding. In like manner, an absorp- The same 

 tion of nitrogen was observed after starving the animal, and then fasting. 

 submitting him to a diet very different from his ordinary one, and also 

 during sickness. 



3d. The ratio between the quantity of oxygen contained in the car- 

 bonic acid and the quantity consumed depends more on the Influence of 

 nature of the food than on the class to which the animal be- food and fast- 

 longs, being, when the animals are starving, the same as it is ing * 

 when they are fed upon meat, or perhaps a trifle less. From this the 

 interesting conclusion may be drawn that a starving animal furnishes to 

 the air of respiration his own substance, which is of course of the same 

 nature as the flesh he eats when dieted on meat. All hot-blooded ani- 

 mals present, when they are starving, the respiration of carnivora. The 

 ratio for the same animal varies from 0.62 to 1.04, according to the na- 

 ture of the diet. 



