268 Chapter XVIII 



d'Olen and ascend at the required speed. The ascent is a steep 

 mountain path all the way from a small pond, right up to the Albergo : 

 thence a few minutes' walk over some rocks to the right brought us 

 to the Laboratory. Everything was read} r when the subject of the 

 experiment came in ; we took his alveolar air before his respirations 

 slackened, then he was at once bled ; the blood was divided into 

 two portions, one given to Mathison and Roberts for the acid deter- 

 minations, the other retained by Camis and myself for the determina- 

 tion of the dissociation curve at the subject's alveolar C0 2 pressure, 

 i.e. the dissociation curve of the man as he stood. 



Parallel climbs at Carlingford and at Col d'Olen were made by 

 Roberts and myself. Let me first discuss those in which the indi- 

 vidual endeavoured in each case to do his climb with the same 

 amount of effort at the two places. 



Roberts in each case climbed as fast as he could walk. He did 

 not run. The time occupied at Col d'Olen was 33 minutes and at 

 Carlingford 20 minutes ; that is, he was able to walk about half as 

 fast again with the same degree of effort at Carlingford as at Col 

 d'Olen. The degree of meionexy induced at each place can be 

 judged from the change in the value of K in the equation 



y Kx n 



100 ~ 1 + Kx n ' 



Values of K (Roberts}. 



The changes in K which were induced by the two ascents were 

 almost identical. The curves are given in Fig. 128 and are scarcely 

 to be distinguished. Climbing at a much slower rate the experiment 

 made upon me yielded much the same result as that just quoted. In 

 each case I climbed at such a rate that I could just respire efficiently 

 without departing from nasal breathing; had I gone faster I should 

 have had to breathe through my mouth. 



