418 



Dr. W. Marcet. 



[Feb. 10, 



II. " Experiments undertaken during the Summer, 1880, at 

 Yvoire (1,230 feet), Courmayeur (3,945 feet;, and the ' Col 

 de Geant ' (11,030 feet), on the Influence of Altitude on 

 Respiration." By William Marcet, M.D., F.R.S. Re- 

 ceived January 24, 1881. 



Former communications on the influence of altitude on respiration 

 have appeared in the "Proceedings of the Royal Society" for 1878 

 and 1879. I have continued the inquiry ; and my present object is to 

 give an account of my latest investigations on that subject. 



I must beg leave to premise that a work of this kind is not free 

 from difficulties ; some of these are of a physiological nature, and 

 refer to the task of taking into account the different circumstances 

 bearing on the state of the body at the time of the experiment ; 

 respiration is, if I may so express it, so delicately balanced in its 

 relations with the other functions, that any one of them becoming 

 either quiescent or in a state of activity reacts immediately upon it. 



Then the capacity of the bags for collecting the air expired gave 

 some little trouble to determine accurately ; and, moreover, the manipu- 

 lations, which would require both care and practice to be carried 

 on satisfactorily in a laboratory where all that can be wanted is 

 at hand, were found much less easy to perform in the open air, 

 at the summit of some high mountain, in a cold cutting wind, and 

 where the omission of a trifling article, such as a cork or a piece 

 of string, might render much labour useless. There is also a circum- 

 stance in a work of this kind having a tendency to detract from the 

 value of its results, inasmuch as what is observed with one person may 

 not apply to another. It is not easy to find many people ready to 

 submit to a stay of several days in the Alps, at altitudes ranging up 

 to 10,000 feet and above ; and I know by experience that the increased 

 length of time required to repeat the experiments on different persons 

 may prove very inconvenient. This last summer, however, I was 

 most fortunate in obtaining the company and help of a young gentle- 

 man from Geneva, M. Elie David, the assistant of the Professor of 

 Natural Philosophy at the University of that town, Professor Wart- 

 mann. M. David submitted to experiment with great patience and 

 much intelligence, and the results obtained on both of us may be 

 accepted as perfectly trustworthy. 



My method of investigation has been much improved since my last 

 paper was communicated to the Royal Society, and the substitution of 

 the vacuum process for the aspiration with water, in order to transfer 

 air from the bag into the cylinder for analysis, has added not a little 

 to the accuracy of the results. New and larger india-rubber bags 

 than those used at first have been made, of improved material, and 



