310 THE BLOOD. 



The methods for the determination of the true reaction of animal 

 fluids, also the blood, have been given in Chapter I. For the true 

 alkalinity of the blood, as first shown by HOBER and especially by 

 HASSELBALCH and LUNDSGAARD, the carbon dioxide is of the greatest 

 importance in that with an increasing carbon-dioxide tension the con- 

 centration of the H ions increase. Thus HASSELBALCH and LUNDS- 

 GAARD 1 found that a rise in the carbon-dioxide tension of 30-50 mm., 

 that is a rise of 20 mm., increased the concentration of the H ions about 

 36 per cent. 



For the determination of the true reaction the temperature at which 

 the measurement is made is of the greatest importance. As the dis- 

 sociation constant of water strongly rises with the temperature, the 

 HO ion concentration of the blood must rise with the temperature, and 

 we can believe that the alkalinity of the blood at body temperature 

 must be 2-3 times greater than when measured at 18 and that this 

 alkalinity increases 15-20 per cent when the normal temperature of the 

 body (38) rises to that of a high fever (42). 



The true alkalinity of the blood is somew r hat variable under different 

 conditions. In this connection it must be remarked that also age and 

 other conditions have an action upon the alkalinity. As the determin- 

 ations are made with different, and not always exact methods, and some- 

 times without consideration of the action of carbon dioxide and tem- 

 perature, it is extremely difficult to give satisfactory average results. 

 Under these circumstances it is perhaps sufficient to refer to the figures 

 given in Chapter I (page 76). 



The alkali of the blood as above mentioned exists in part as alkaline 

 salts, carbonate and phosphate, and partly in combination with protein 

 or haemoglobin. The first are often spoken of as readily diffusible alkalies, 

 while the others are not or are only diffusible with difficulty (see page 

 268) . The quantity of the first, in human blood, is about one-fifth of the 

 total alkali (BRANDENBURG). The readily as well as the difficultly 

 diffusible alkali is divided between the blood-corpuscles and plasma, and 

 the blood-corpuscles seem to be richer in difficultly diffusible alkali than 

 the plasma or serum. This division may be changed by the influence of 

 even very small amounts of acid, even of carbonic acid, and also, as shown 

 by ZUNTZ, LOEWY and ZUNTZ, HAMBURGER, LIMBECK, and GtJRBER, 2 



1898. See also Maly's Jahresber., 29, 30, and 31; Salaskin and Pupkin, Zeitschr. f. 

 physiol. Chem., 42, and O. Folin, ibid., 43; Laitinen, Hammarsten's Festschr., 1905 ; 

 Westenrijk, Arch. f. exp. Path. u. Pharm. Suppl., 1908, Schmiedeberg-Festschrift. 



1 The literature may be found in Sorenssen, Messung und Bedeutung der Wasser- 

 stoff-ionkonzentrationen, Ergbn. d. Physiol., 12; Hasselbalch and Lundsgaard, Bioch. 

 Zeitschr., 38, and Skand. Arch. f. Physiol., 27; Hasselbalch, Bioch. Zeitschr., 30; Lunds- 

 gaard, ibid., 41. 



2 Zuntz, in Hermann's Handbuch der Physiol., 4, Abt. 2; Loewy and Zuntz, 



