Abstract
The present study is based largely on material observed several years ago in Munich in the clinic of Prof. Friedrich Müller. The object of the study was to determine by means of exact methods, (1) the existence of a high color index in pernicious anemia, (2) the magnitude of the elevation of the color index, and (3) the explanation of the phenomenon.
The calibration of the pipette and the dimensions of the counting chamber used for the erythrocyte counts were checked by special methods. The hemoglobin determinations were made spectrophotometrically (spectrophotometer of König, Martens and Grünbaum, Nernst filament as light source). The manner in which the hemoglobin concentration may be calculated from a measurement of the light absorption follows from the equation for the diminution in the intensity of homogeneous light on traversing a planparallel layer of a colored solution:
in which I = initial intensity, I' = final intensity, k = a constant, I = linear thickness of the absorbing layer, and c = the concentration of the colored substance. I'/I can be measured with spectrophotometer. When this has been done with a solution of pure oxyhemoglobin of known concentration in an absorption tube of known length k can then be calculated. After the value of k has been determined for pure oxyhemcglobin from human blood the concentration of hemoglobin in lalied human blood can be derived from a measurement of I'/I. Oxyhemoglobin from ox blood may be conveniently substituted for human hemoblogin in the determination of k since it was shown in Tiibingen that the constant has the same value for both henloglobins. In the present study homogeneous light was not enlployed, but the measurements were made in a very narrow interval in the spectrum (about 4 pp).
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