RESPIRATION 195 



suffering from severe alkalosis although the ''alkaline reserve" or 

 titration alkalinity of their blood was greatly diminished; and 

 similarly they were suffering from severe acidosis although the 

 "alkaline reserve" of their blood was greatly increased. 



It was these observations that led Yandell Henderson to the 

 same conclusion which we reached — namely, that in the anoxae- 

 mia of high altitudes there is a condition of alkalosis, and not of 

 acidosis, in spite of the greatly reduced titration alkalinity or 

 "alkaline reserve" of the blood. 



A ready method of interfering temporarily with the regulation 

 of blood reaction by the lungs is forced breathing. This can be 

 continued for a considerable time if it is employed in moderation. 

 Leathes** found that if forced breathing is continued for some 

 time the urine becomes alkaline to litmus, and the titration alka- 

 linity has still more recently been investigated by Davies, J. B. S. 

 Haldane, and Kennaway.^^ The titration alkalinity is, however, 

 not so striking as after a large dose of sodium bicarbonate has been 

 taken. The same observers found that after a large dose of sodium 

 bicarbonate there was not only a rise of as much as I per cent in the 

 alveolar CO2 pressure for some hours, but the available alkali in 

 the blood (as shown by the dissociation curve for CO2) was 

 markedly increased, while there was also a great increase in the 

 titration alkalinity of the urine. Large quantities of bicarbonate 

 (readily determined by the blood-gas apparatus) were present in 

 the urine, which effervesced briskly on the addition of acid, though 

 the actual alkalinity of the urine was of course only feeble, since 

 the CO2 acted as a buffer. The titration alkalinity (after removal 

 of liberated CO2) was equivalent to nearly i per cent of HCl. The 

 ammonia had completely disappeared from the urine, and this 

 was also the case after forced breathing, although such a degree 

 of forced breathing as was practicable did not appreciably dimin- 

 ish the available alkali in the blood within one and one-half 

 hours. A stay of several hours in air containing 5 to 6 per cent of 

 CO2 was also not sufficient to increase appreciably the available 

 alkali of the blood, although the titration acidity of the urine was 

 increased, along with increased excretion of ammonia. Collip has, 

 however, found that, as might be expected from the change in 

 distribution of acid and alkali between plasma and corpuscles 



** Leathes, Brit. Med. Journ., Aug. 9, 1919. 



"Davies, J. B. S. Haldane, and Kennaway, Journ. of Physiol., LIV, p. 32, 

 1920. 



