THE CAUSE OF MOUNTAIN SICKNESS 223 



of animals submitted to this pressure he supposed that a marked 

 difference in tension between the blood an'd the alveolar air is 

 necessary to drive the blood through the alveolar wall. Hufner's 

 curve has been received for many years into the text-books. Loewy 

 and Zuntz have shown that Hufner's methods of preparation 

 are at fault, and that the dissociation curve of fresh living blood 

 is quite different to that of prepared haemoglobin or laked blood, 

 and, in fact, closely agrees with that worked out by Bert. 



Comparing the saturation of laked and normal blood, Durig 

 and Zuntz obtained the following figures : 



O 2 Tension. 

 24-07 mm. 



23-10 mm. 



Sat. of Normal Blood. 

 58-74% 



Sat. of Laked Blood. 



78-84% 



which show the great effect produced by the mere solution of the 

 haemoglobin. The use of alcohol in preparing crystallised Hb 

 still further changes the dissociation curve. 



In the blood-corpuscles, the haemoglobin is held in a suspended 

 condition, and the other constituents of the corpuscles modify the 

 dissociation of oxygen. 



The following figures have been worked out by A. L6ewy from 

 human blood drawn from the median vein. He shook the blood 

 at body temperature in a pear-shaped vessel with atmospheres of 

 known composition, by a shaker which instantly threw the blood 

 into foam. 



The Hb is 70 per cent, saturated with 2 at i atm. press., 

 and 50 per cent, saturated at J atm. It is owing to thi? 

 slow increase in dissociation that we are able to endure high 

 altitudes. 



