FUNCTIONS OF ANIMALS. 



(3.) A rabbit of the volume 48 cubic inches, in thirty minutes 

 converted 28-22 cubic inches of oxygen into carbonic acid. 



The mean of these three experiments gives the consumption 

 of oxygen gas by the respiration of a rabbit, to amount to 27*25 

 cubic inches, or at the rate of 54^ cubic inches in the hour. 

 Now, it has been stated above that the mean quantity of carbo- 

 nic acid gas formed by the respiration of a man in an hour is 

 373-24 cubic inches, which is almost seven times greater than 

 the quantity formed by the respiration of the rabbit. The ave- 

 rage specific gravity often men tried by Mr Robertson was 0-89, 

 and the average weight of each 145*9 Ibs. or 4545 cubic inches,* 

 or more than ninety-two times the bulk. Thus, it appears, (sup- 

 posing Brodie's experiments to approach accuracy,) that the 

 quantity of carbonic acid formed by the respiration of the rab- 

 bit is more than ten times as great (making allowance for the 

 difference of bulk) as in man. 



(1.) Mr Brodie having procured two rabbits of the same size 

 and colour, divided the spinal marrow in the upper part of the 

 neck of one of them. An opening was made in the trachea by 

 means of which artificial breathing was kept up for half an hour. 

 The heat of the rectum at the commencement of the experiment 

 was 97, at its termination 90. The carbonic acid gas formed 

 was 20-24 cubic inches, or about one-fourth less than in the liv- 

 ing rabbit. The second rabbit killed at the same time, and in 

 the same way, was placed in the same circumstances with the 

 first, but without artificial respiration. At the end of the half 

 hour, the thermometer in its rectum stood at 91. 



(2. ) Two rabbits were killed by inoculation with woorara poi- 

 son. In the first the lungs were inflated by artificial inspiration 

 for half an hour. The thermometer in the rectum sunk from 

 98 to 91. The carbonic acid formed was 25-55 cubic inches, 

 or only one-sixteenth less than the normal quantity. The second 

 rabbit was placed in exactly the same circumstances, but without 

 artificial respiration. In half an hour, the thermometer in the 

 rectum sunk to 92. 



(3.) Two rabbits were killed by woorara. In one the respira- 

 tion was kept up artificially for thirty-five minutes. The ther- 

 mometer in the rectum sunk from 97 to 90. The carbonic 

 acid formed was 31-75 cubic inches, which is at the rate of 



* Phil. Trans. 1757, p. 30. 



