The effect of altitude 259 



equivalent of 0'02 / lactic acid. After we had been at Col d'Olen some 

 ten days we went up to the Margherita. The ascent is about 5000 feet, 

 we made it in seven hours, of which we rested for perhaps an hour at the 

 Capanna Gnifetti ; on reaching the summit there was again a further 

 large accession of acid to the blood. It reached 0'54 / . This again 

 had ebbed to some extent by the following morning. At present we 

 are only discussing the question of the condition of the blood when 

 the person under observation is at rest or at all events not exerting 

 himself. There is the most distinct and definite evidence that the 

 blood changes at each different altitude, in that apart from the C0 2 

 present the blood gains in acid, or loses in alkali, at all events that 

 its reaction alters in the direction of decreased alkalinity at the 

 higher altitudes. 



(3) Though the method we have described, namely, that of 

 measuring the reaction by the affinity of the blood for oxygen, proved 

 most satisfactory and was operated with great skill and rapidity by 

 Mathison and Roberts, we naturally wished to have some other methods 

 at our disposal. One of these was the method of Boycott and Chis- 

 holm (1) for determining the reaction of blood. It depends upon the 

 fact that the haemoglobin precipitates at a definite acidity. The 

 blood is therefore titrated with acetic acid until a precipitate appears, 

 the original reaction being calculated from the amount of acid 

 necessary to bring the blood to the point of precipitation. This 

 method was not used so systematically as that previously employed. 

 It gave qualitatively the same result (2) . 



Lastly, as it seemed to us probable that the acidosis which we had 

 observed in Teneriffe might have been due to a lactic acidosis, we 

 determined to make actual determinations of the lactic acid present 

 by Ryffel's (3) method (see Chapter XV). Let us state precisely what it 

 is that this method estimates. It is the total quantity of the radicles 

 of the -OH organic acids. It therefore has to do with something 

 essentially different from the others ; the others are a measure of the 

 hydrogen ion concentration, for it has been shown by Mathison that 

 the change in affinity of the haemoglobin for oxygen when acids are 

 added to the blood depends upon the concentration of hydrogen ions, 

 and the same has been shown by Boycott and Chisholm for their 

 method. But Ryffel's method is different ; it measures the lactic acid 

 radicle irrespective of the degree of ionisation of the acid or of the 

 bases with which it is united. Moreover it includes an} 7 other a-OH 

 acids which may be present in the solution. 



172 



