THE BARRIER-LAYER PHOTOELECTRIC CELL 



157 



reading scale. The operator can plot his own transmissivity concentra- 

 tion curve on the attached scale, graduated from to 100 arbitrary units. 



Standardizing scale 



fPry sl'd | 



| Zero | mg./lQO ml 



20 40 



Sugar in blood or urine |Lam P | 



60 80 100 120 140 160 180 200 220 240 260 280 320 360 4^0 k 



Length of each scale 111 mm 

 A brief statement of the technique used for each scale 

 a Accurate quantitative albumin determinations using a modified Exton's Reagent. 

 b Calcium by Brigg's method, modified by Roe and Kahn. Phosphorus by Benedict's method. 

 c Turbidimetric test using silver nitrate. Rapid and accurate. 

 d Cholesterol determination by the modified Bloor or Leiboff methods. 

 e Creatinine determination by the commonly accepted Folin and Wu method. 

 / Employs acid hematin method. Scale standardized by Van Slyke oxygen capacity method. 

 9 Determination by the well known phenolsulphonphthalein method. 

 h Sugar determinations by the commonly accepted Folin and Wu method. 

 i Urea nitrogen or nonprotein nitrogen determinations by Folin and Wu method. 



Fig. IV-17. A set of nine colorimetric calibration scales, for clinical laboratory 

 determinations. (By courtesy of Fisher Scientific Company, Pittsburgh, Pa.) 



In this instrument, other scales which are engraved by the maker to 

 read directly the concentrations in milligrams per 100 ml may also be 



