604 PHYSIOLOGY OF ALPINISM 



guished; nor can it be in any degree predicted that sojourn 

 at a moderate elevation will necessarily bring about pro- 

 portionately a more powerful ventilation of the lungs. 



At very high elevations (above 4500 metres) the danger 

 of dyspnoea undoubtedly becomes impending. Even trifling 

 interference with breathing, as from lacing the shoes, may 

 call out a feeling of oppression, and ability to perform 

 labor seems very much reduced. Yet even at a height of 

 6000 metres, which was attained by Whymper on Chim- 

 borazo, mountain sickness may fail to appear. In direct 

 connection with the dyspnoea there also occurs sleepless- 

 ness. The members of Himalaya expeditions, usually at 

 heights of about 6000 metres, on going to sleep were almost 

 immediately wakened by dyspnoeic symptoms. The breath- 

 ing may even assume a periodic character, quite like the 

 Cheyne-Stokes type. The woman Himalayan climber, Mrs. 

 Bullock- Workman, believes that the greatest difficulty at- 

 tending the attainment of the highest mountain peaks of 

 the world is the loss of sleep, as naturally the number of 

 sleepless nights increases with the height of the mountain. 



Acapnia. In connection with mountain sickness acapnia 

 is a subject which has also been frequently discussed. The 

 fact that a stay in very rarefied air is better sustained pro- 

 vided carbonic oxide is mixed with the respired atmosphere 

 was proved some time since by the Zuntz school. There is 

 reason, doubtless, in this relation to think that the carbonic 

 acid, as has been previously pointed out, may be concerned in 

 increasing the dissociation tension of oxyhaemoglobin and 

 thus facilitating the supply of oxygen to the tissue. Accord- 

 ing to the acapnia theory of Angelo Mosso the symptoms 

 of mountain sickness may be thought of as due, not so much 

 to the lessened pressure of oxygen, as to a carbonic acid 

 impoverishment of the blood and to the loss of the normal 

 stimulative excitation which carbonic acid exercises upon 

 the respiratory centre. The demonstrative force of the 

 material brought forward by the Mosso school in favor of 



