AIR AND LIFE. 181 



asked him to help me to keep on my animal, and I was taken with such 

 pain, sobbing, and vomiting-, that I thought I should die, and, moreover 

 after having vomited food, phlegm (mucous matter), and bile, yellow 

 first and afterwards green, I even threw up blood, such pains had I in 

 my stomach; and I am sure that if it had lasted longer I would cer- 

 tainly have died. As it was it lasted only three or four hours, till we 

 had reached a much lower region. And not only men, but animals also 

 were affected." And further on, "I feel confident that the substance of 

 the air in such places is so subtle and thin that it is unsuitable for human 

 respiration, which requires it thicker and better adapted." This was 

 written three hundred years before the time of Priestley and Lavoisier, 

 and yet the expressions used by Acosta are really most happy. Atmos- 

 pheric air in the altitudes is too thin, too rarefied, too subtle for the 

 respiration of superior organisms. The evil described by Acosta is 

 that which, in different countries and places, is named puna, soroche, 

 veta, mal des montagnes, mountain siclcness, balloon sickness. It has been 

 more recently and frilly described and investigated by Tschudi, Lortet, 

 and many others; each has noticed the vertigo, vomiting, anxiety, and 

 fainting which characterize it; and exact experiments — those of Lortet 

 and Chauveau, among others — have shown that respiration is dimin- 

 ished and at the same time accelerated; intense muscular pains have 

 been noticed, and also circulatory and nervous symptoms, which end 

 in paralysis and death if the perturbations continue, as in case of the 

 Zenith catastrophe. 



While it would be quite superfluous for our present purpose to re- 

 view the opinions which have at different times been entertained con- 

 cerning the cause of these dangerous perturbations, we may briefly 

 summarize the explanation thereof recently given by Paul Bert and 

 others. 



This is quite simple. The symptoms and death are due to a diminu- 

 tion in the tension of oxygen, which is itself due to the rarefaction of 

 that gas. As everyone will understand, if the same volume contains 

 in high altitudes less weight of air than in low altitudes or at the sea 

 level, it follows that in the former condition there is less air avail- 

 able, less of each constituent, less oxygen. In the heights of the 

 atmosphere air is made up of the same elements as below, but they are 

 less in quantity although the proportions are the same; air is dilated, 

 rarened, thinner, less dense, and of the essential element — oxygen — 

 a smaller quantity is inhaled at each respiratory movement, although 

 the volume of inspired air is the same. Under such circumstances, as 

 Paul Bert's investigations go to show, decrease of pressure kills, not 

 mechanically, but by a chemical process. High altitudes kill because 

 they induce a state of anoxyhremia, a state in which the blood is 

 deficient in oxygen.. The animal — or man — in rarefied air, dies for the 

 same reason that one dies in a confined atmosphere; in both cases 

 there is an insufficiency of oxygen. 



