are equivalenl quantities of fre< H,CO I bicarl 



— the II ion concentration will be exactly I the -I 



constant of carl ic acid; therefor* 0.000,000,5 N P 6.31 



five times the value of neutrality, .1 \ P 7 : l 



times as much free carbonic acid as bicarboni I \ theo the I! 



concentration will be fifty times that of neutrality, i. • *. — 



0.000, ,5 0.000,005 P 5.3] ; if ther. ten tin 



acid than bicarbonate, the II ion concentration will be one-half thai 



neutrality, i. e., =rj 0.000,000,5 0.000,000,05 P 7 ' 



if twenty times less, one fourth P 7.6 . Since a 



bicarbonate is actually presenl in blood enough to yield fron 



< ' n _- per LOO c.c. of blood see page 391 . and th< 



undergoes fluctuations which ar< only trivia] when compared with tl 



which have I □ chosen in the above examples, it is clear thai 



be very little change in the H-ion concentration of the blood in com] i 

 with tho variations which would occur were no bicarbonate present. 



Another weak acid which acts like carbonic in maintaini - 



ity is acid phosphate .MM I' 11 . and for the Bam< □ namely. | 



its dissociation constanl is of similar magnitude to the II ; "': 



tration. Although the hi 1 plasma itself contains much less pho 



than bicarbonate, the 1 i-.^n<-- contain a considerable amount, which 



ahles them to maintain their neutrality. This on of 1 



phosphates is styled the buffer action, meaning that it mp 



dowil the effect oil the H imi e. .1 icell t fat ion which addit 



alkalies would otherwise have. As pointed oul by I '• 

 better word to use would be "tampon action." sine,. th< 

 actually soak up much of the added II or OH' io - [1 

 to the fluids of the higher animals, but is widely 



throu ghoul nature; for example, in th< n and in the flui 



organisms and animalcules see I. J Hendersoi 



Although the actual reaction by which neutrality is m. 

 purely of a physicochemical natui 

 made so thai the acid and b ibstan< 



supplied and those produced bj the react 

 quires Tl e ii r ■ ^i)>i>1<i is parti} 



The exogenous Bource is the basic and in 



food; and although we do nol ordinarily 

 of these substances i maj d 



persistent udniinistration 

 endogenous source dcpei 



