68 Dr. Marcet. Absorption of Oxygen and [June 4, 



The mean ventilation of the lungs, by which expression I con- 

 clude Messrs. Hanriot and Richet mean the sum of the air 

 inspired and expired, amounts, according to these authors, to 10 litres 

 of air per kilo, weight of the body per hour. This result agrees, 

 within certain limits, with those T have obtained. The sum of the air 

 inspired and expired in each experiment gives, in my case, a maximum 

 of 9'94 litres per kilo, weight per hour, and a minimum of 8'33 litres, 

 with a mean of 9'12 litres, which is near to Messrs. Hanriot and 

 Richet's figure of 10 litres. Mr. Russell's mean pulmonary ventila- 

 tion is decidedly less than mine, and lower than the figure obtained 

 by the French authors, amounting to a maximum of 9'51 litres and a 

 minimum of 6'87 litres, the mean being 8'13 litres. It is therefore 

 obvious that the pulmonary ventilation varies per kilo, weight of 

 body, according to different people. Messrs. Hanriot and Richet 

 apparently experimented only on a single person. 



The volume of carbonic acid in 100 of expired air appears decidedly 

 low in Messrs. Hanriot and Richet's experiments, amounting to a 

 mean of 3*30. In the experiments which form the subject of the 

 present paper, the corresponding proportion varied, for myself 

 between 4'53 and 5'14, and for Mr. Russell between 5'38 and 5'90. 

 These proportions, to which I have drawn attention in former com- 

 munications, vary not only with different individuals, but with the 

 same person under different circumstances. The relation between 

 the oxygen consumed and C0 2 produced is decidedly smaller in Messrs. 

 Hanriot and Richet's experiments than in my own ; those gentlemen 

 find the mean relation in question to be 0'78, while the mean from 

 my experiments on two different persons yield 0'871. 



The second part of the present communication deals with the respira- 

 tion of air containing from 2'5 to 4 per cent, of carbonic acid. The 

 mixture was made by introducing carbonic acid, prepared from marble 

 and hydrochloric acid, into a certain volume of air drawn into one of 

 the bell- jars. The mixture was first of all analysed for the determination 

 of the C0 8 it contained, and then it was inspired through the nose, 

 by means of a well -fitting nose-piece, and expired into the other 

 bell-jar through the mouth. The first five or six inspirations were 

 used for rinsing out the lungs and the bell-jar, and were driven 

 out of the second bell-jar through a T-piece, while the person 

 under experiment was expiring into the open air; this was easily 

 effected by means of the three-way stop-cock ; then the stop-cock 

 was again turned, and the expired air collected in the bell-jar while 

 the time was taken. The effects produced were a sensation of want 

 of air and a considerable increase in the volume of air breathed per 

 minute. The air expired, during a period of from 2 to 4 minutes, 

 was collected for experiment ; but the breathing of the air and C0 2 

 was carrier) on altogether for 4 or 5 minutes. No lasting ill effects 



