MOUNTAIN SICKNESS. 97 



degree of distress with the direction of the wind ; but this 

 is a subject which was much noticed by the Schlagintweits, 

 and by numerous other observers, who found that they were 

 most distress when there was a wind from some particular 

 direction. There is no reason for supposing that this was 

 due to temporary variations in the barometric pressure — as 

 such an obviously possible explanation could not have been 

 very easily overlooked by the Schlagintweits. It is certain 

 that air which has passed over a large area of snow melted 

 by the sun will have suffered a diminution of its oxygen. 

 If this idea be correct, such winds ought to be most 

 distressing in the afternoon when the quantity of water 

 set free by the melting of the snow is greatest. On 

 being frozen again at nightfall, the melted snow will give 

 off relatively a large proportion of oxygen, which may 

 explain why Conway and his party felt so much better 

 at night. It is possible that the increased distress felt by 

 Conway and others in sunshine as compared with shade 

 or cloudy weather, was in part due to the increased demand 

 for oxygen by the body when warmed by the sun's 

 rays. Another point that strikes one in going over the 

 literature of Mountain Sickness is that sometimes, especially 

 in the Andes, dangerous symptoms show themselves at 

 altitudes below 17,000 feet in persons riding on horse or 

 mule-back, and where there is therefore no question of over- 

 exertion. I have been at pains to follow out some of these 

 cases, and find that previous attacks of malarial fever are 

 recorded. The diminished, amount of haemoglobin in the 

 blood which follows malaria will, in these cases, readily 

 account for the asphyxia which shows itself, and may cause 

 death in men and animals at heights below 1 7,000 feet. 



While thanking Conway most cordially for all he has 

 done in the past in adding to our knowledge about mountain 

 sickness, I would venture to ask him, when next he goes 

 mountain climbing above 17,000 feet, to purchase before 

 leaving England a binaural stethoscope, and get some 

 medical friend to put him in the way of recognising a heart- 

 murmur, and to use this stethoscope on himself and others 

 of the party during or immediately after exertion. 



