THE PHENOMENA OP HUMAN RESPIRATION. 
7 
The experiments were made by determining as carefully as possible the volume of 
air expired within a given time, and finding tlie amount of carbonic acid this air 
contained by means of Pettenkoper’s method carried out with the aid of an instru¬ 
ment I had constructed for tliat purpose. Then, knowing the weight of carbonic acid 
in a given volume of air, it was easy to find, by a very simple calculation, the volume 
of air (reduced to 0° and 7G0 mm. pressure) corresponding to, or holding, 1 grin, of 
carbonic acid. The method and instruments employed in this inquiry have been 
fully described in a previous communication. 
Being desirous of ascertaining whether at such stations as those frequented by 
invalids the same effects were produced on the function of respiration as at greater 
elevations, I repeated the experiment in the year 1882 on the Bigi Mountain, in 
Switzerland, in the company of a young engineer, Mr. B. Thury. As the results 
obtained have never been published, beyond a short reference to them in a paper to 
the Alpine Club, I shall beg to include a tabular statement of these experiments in 
the present communication. The inquiry made on the Bigi confirms in every way the 
law ruling the chemical phenomena of respiration at different altitudes. Mr. Thury 
submitted alone to these experiments. 
Fifteen expeiiments were made on the 3rd and 4th of September near Geneva, at 
an altitude of 1230 feet (375 metres), mean barometer pressure of 728 mm. and 
temperature of 15”'9 C. ; and eighteen experiments were made as soon as possible 
afterwards at the Bigi Staffel, at a mean pressure of 639 mm. and mean temperature 
of 7°'6 C. during the experiments. The Bigi Staffel is situated at an elevation of 
5230 feet (1594 metres), giving a difference of altitude of 4000 feet, or 1219 metres, 
and of 89 mm. mean pressure, between the two stations. It might have been expected 
that more carbonic acid would be exhaled in a given time on the cold mountain station 
than in the valley of Geneva, and this turned out to be the case ; as, while a mean of 
0‘350 grm. 00^ was expired near Geneva the lower and warmer station, this figure 
rose fo a mean of 0'445 grm. at the higher or colder station—giving an excess of no less 
than 21 per cent, of carbonic acid for the Bigi. The amount of air expired, say breathed, 
for the expiration of 1 grm. of carbonic acid, reduced to 0° and 760 mm., was 10'78 litres 
in the Geneva valley, and only 9 "45 litres on the Bigi station. Therefore, for a mean 
difference of 89 mrn. atmospheric pressure (including the influence of reduced tempera¬ 
ture), less air by 12 per cent, was breathed on the m.ountain to supply the oxygen 
required by the body to burn the same amount of carbon as in tlie valley. 
