1891.] Formation of Carbonic Acid in Human Respiration. 71 



Dr. Marcet. 



3rd. That the volume of oxygen absorbed per minute is greatly 

 increased, my own mean amounting to 103 c.c., and Mr. Russell's 

 to 155 c.c., instead of 32*2 in my case and 37*5 in the other. 



4th. That the proportions per cent, of oxygen absorbed in the air 

 inspired are increased in both cases to a mean of 1'39 against 0'66, 

 and to a mean of 1*98 against 0*75 in ordinary breathing. A corre- 

 sponding increase is observed in the proportion of oxygen absorbed to 

 the oxygen inspired, 



5th. That the weight of oxygen consumed by the body per hour is 

 considerably increased, amounting to a mean in my case of 25*42 

 grams, against 21*37 grams, and with Mr. Russell of 30*95 grams 

 against 28*66 in ordinary breathing. 



6th. That the weight of carbonic acid expired per minute is con- 

 siderably reduced, amounting in my case to a mean of 0*378 instead 

 of 0*430, and with Mr. Russell to a mean of 0*402 instead of 0*578 

 expired in normal respiration. 



These experiments, although but few in number, suffice to show 

 that when air is breathed containing from 2*5 to 4 per cent, of 

 C0 2 the amount of oxygen consumed is much greater than in 

 ordinary breathing, while the carbonic acid expired is very much less. 

 There must consequently remain in the blood a considerable amount 

 of oxygen to be transformed into an excess of CO 2 besides the pro- 

 portion required towards the 'other functions of the body. 



* The analyses following fig. 2 do not really correspond, but are made under 

 similar circumstances of food, temperature, &c., and are therefore made to compare 

 with each other in this table. 



