BIOLOGICAL APPLICATIONS 217 



It has been shown by Marshall (39) that the major part of the 

 neutralizing power of saliva is likewise attributable to its inor- 

 ganic constituents. 



It would not be safe, however, to conclude from these results 

 that the part played by the proteins in maintaining the neutrality 

 of the tissues is not, possibly, equal in magnitude to, or even 

 greater than, that played by the bicarbonates and acid phosphates. 

 Thus, referring to the tables in section 2 it will be seen that 

 100 cc. of a 1.5 per cent solution of potassium caseinate, in pass- 

 ing from the reaction 0.34 X 10~ 7 H+ to the reaction 1.14 X 10~ 7 

 H+ neutralizes the equivalent of 25 cc. of N/ 10 HC1; a 3 per 

 cent solution (the concentration of casein in cow's milk) would 

 therefore neutralize, in passing from the former to the latter of 

 the above reactions, the equivalent of one-half its volume of 

 N / 100 HC1. The part played by the casein of milk in main- 

 taining the neutrality of this tissue-fluid must therefore be of 

 very considerable importance. In the tissues, not only are the 

 proteins more concentrated than they are in the tissue-fluids, 

 but, owing to the predominance of nucleo-proteins which have 

 a high combining-capacity for bases, their power of maintaining 

 the neutrality of the solutions is not improbably even higher 

 than that of the majority of the proteins which occur in the 

 tissue-fluids. We are not, at present, in the possession of any 

 data which would render an estimate of the relative importance 

 of these factors, for the maintenance of the neutrality of the 

 tissues themselves, in the slightest degree reliable. 



LITERATURE CITED 



(1) Abegg, R., and Cummings, A. C., Zeit. f. elekt. Chem. 13 (1907), 



p. 17. 



(2) L'Agostino, E., and Quagliariello, G., Nernst Festschr. (1912), p. 27. 



(3) Bjerrum, N., Zeit. f. physikal. Chem. 53 (1905), p. 428. 



(4) Blasel, L., and Matula, J., Biochem. Zeitschr. 58 (1914), p. 417. 



(5) Bugarszky, S., and Liebermann, L., Arch. f. d. ges. Physiol. 72 (1898), 



p. 51. 



(6) von Bunge, G., Zeit. f. Biol. 12 (1876), p. 191. 



(7) von Bunge, G., "Lehrbuch der physiol. und pathol. Chem.," Leipzig, 



1889. 



(8) de Corral, J. M., Biochem. Zeitschr. 72 (1915), p. 1. 



(9) Erb, W., Zeit. f. Biol. 41 (1901), p. 309. 



(10) Farkas, G., Math. Estermeszettud. Ertesito. 21, p. 45; cited after 

 Maly's Jahresber. f. Tierchem. (1902), p. 274. 



