322 PORTILLO PASS. [chap. xv. 



after resting for a few seconds the poor willing animals started of 

 their own accord again. The short breathing from the rarefied 

 atmosphere is called by the Chilenos " puna ;" and they have 

 most ridiculous notions concerning its origin. Some say " all 

 the waters here have puna;" others that "where there is snow 

 there is puna;" and this no doubt is true. The only sensation 

 I experienced was a slight tightness across the head and chest, 

 like that felt on leaving a warm room and running quickly in 

 frosty weather. There was some imagination even in this ; for 

 upon finding fossil shells on the highest ridge, I entirely forgot 

 the puna in my delight. Certainly the exertion of walking was 

 extremely great, and the respiration became deep and laborious : 

 I am told that in Potosi (about 13,000 feet above the sea) 

 strangers do not become thoroughly accustomed to the atmo- 

 sphere for an entire year. The inhabitants all recommend onions 

 for the puna ; as this vegetable has sometimes been given in Eu- 

 rope for pectoral complaints, it may possibly be of real service : 

 for my part I found nothing so good as the fossil shells ! 



When about halfway up we met a large party with seventy 

 loaded mules. It was interesting to hear the wild cries of the 

 muleteers, and to watch the long descending string of the 

 animals ; they appeared so diminutive, there being nothing but 

 the bleak mountains with which they could be compared. When 

 near the summit, the wind, as generally happens, was impetuous 

 and extremely cold. On each side of the ridge we had to pass 

 over broad bands of perpetual snow, which were now soon to 

 be covered by a fresh layer. When we reached the crest and 

 looked backwards, a glorious view was presented. The atmo- 

 sphere resplendently clear ; the sky an intense blue ; the profound 

 valleys ; the wild broken forms ; the heaps of ruins, piled up 

 during the lapse of ages ; the bright-coloured rocks, contrasted 

 with the quiet mountains of snow ; all these together produced a 

 scene no one could have imagined. Neither plant nor bird, 

 excepting a few condors wheeling around the higher pinnacles, 

 distracted my attention from the inanimate mass. I felt glad 

 that I was alone : it was like watching a thunderstorm, or hear- 

 ing in full orchestra a chorus of the Messiah. 



On several patches of the snow I found the Protococcus nivalis, 

 or red snow, so well known from the accounts of Arctic navi- 



