Figure 3. Absorption spectrum 

 curves obtained from measure- 

 ments on haemolyzed (saponized) 

 dog blood in the 0*007 cm cuvette, 

 illustrating the method used in the 

 direct spectrophotometries deter- 

 mination of percentage satura- 

 tion 10 . Curve HbCh (heavy, 

 solid line), based on mean e 

 values for fully oxygenated blood. 

 The absorption constants (mean 

 z values for a depth of 1 cm and 

 for a concentration of 1 mMII, 

 where M refers to the equivalent 

 weight, on the iron basis, of 

 1 6,700) for Hb0 2 , at the indicated 

 characteristic wavelengths used 

 in the estimation of saturation, 

 are given in the column headed 

 by 0*96. Curve Hb (broken line), 

 based on mean s values upon 

 aliquot s of the samples used for curve Hb0 2 , after deoxygenation by means of 

 solid hydrosulphite or dithionite, Na 2 S 2 4 (O'l mg per ml). The mean z values 

 for Hb, used in the estimation of saturation, appear in the column headed by 

 4*03. Curve M (light solid line), drawn from data upon a sample (used as an 

 example) of a mixture of Hb0 2 and Hb, with total pigment concentration 

 determined independently as cyanmethaemoglobin, MHbCN. Appended data 

 supply the calculations of the fraction of each component in M, and the per- 

 centage saturation of the sample. 2y is the summation of the total change in 

 absorption, HAz, at the specified wavelengths, between Hb0 2 and Hb, while 

 £ p is the summation of the partial change in absorption, at the same wave- 

 lengths, between Hb0 2 and M, the particular mixture of the two components, 

 Hb0 2 and Hb, measured*. For the blood of man the values of E T and the 

 absorption constants are slightly different than for dog blood. For man, 

 -1> == 16*45, and at the respective wavelengths of 600, 578, 562 and 542 m/i, 

 ZHbo* = 0*75, 15*34, 8*50 and 14*61, and z Hb = 4*05, 9*96, 12*75 and 1 1*09 32 . 



Data 



•Sir — ZAzuboi ' Zm> 



0*96- 4*03 - 3*07 at /. 600 

 15*08— 10*46 = 4*62 at I 578 



8*62— 13*16= 4*54 at I 562 

 14-75— 11*09 - 3*66 at /. 542 



r r = 15*89 



E p = EAz Hb0i > z M at same I 



Z p = 0*77 + 1*10 + 1*10 + 0*91 = 3-! 



3*88 

 r = E p ji: T = Fraction of Hb = ry^g 



]—r = Fraction o/'HbO, = 0*756 

 (/—/•) x 100= %75*6 



0*241 



