THE MOUNTAIN CITY OF POTOSI. 4 1 I 



it is also always prudent to be a little careful at first, 

 until the system has had time to become accustomed 

 to the change, and till the " shortness of breath" due 

 to the rarefied atmosphere, which at first affects new- 

 comers at considerable altitudes, even on ascending 

 a small thing like a flight of steps, has gone off. 



When making steep ascents, stop and rest often, and 

 admire the view. * Many a man has permanently injured 

 his heart by overtaxing his strength while ascending 

 mountains, and endeavouring to keep up with practised 

 mountaineers before being in a condition to do so. 



The effect upon the human system of great increases 

 of altitude is often remarkable. There are places, for 

 instance such as Potosi in Bolivia, a great silver mining 

 centre, and one of the highest inhabited localities in 

 the world situated at an altitude of about 13,600 feet 

 over sea level, where, it is said, strangers are seldom 

 able to reside with safety for any great length of time, 

 and cats it is asserted always die if taken there. It 

 is also a curious fact that the native residents are stated, 

 on what seems to be good authority, to be endowed 

 by Nature with a larger chest measurement than the 

 people of the lowlands; they are in consequence able 

 to take into the lungs a larger volume of air at each 

 inspiration, than other people, and thus the highly 

 attenuated atmosphere does not seem to affect them 

 injuriously ; but in the case of people not so constituted, 

 the work thrown upon the heart and lungs is consider- 

 ably augmented, beyond what is natural it follows 

 therefore, that this cannot go on for long, without the 

 risk of grave injury to these organs. 



* See some sensible observations on this head made in Deer-stalking, 

 by Augustus Grimble, 1 886, p. 23. 



