196 PHYSIOLOGY. 



cell. The wedge is graduated at E from 1 to 100, the figures repre- 

 senting the percentage of haemoglobin in the specimen of blood as 

 compared to normal blood containing 13.7 per cent, of hemoglobin. 



Fig. 59. Dare's Hemoglobinometer. (LENHARTZ.) 



The upper figure represents the instrument ready for use (one-half actual 

 size). R, Milled wheel by which the color-prism is rotated. 8, Case inclosing 

 color-prism, showing stage upon which the blood-pipette slides. T, Movable 

 wing pivoted to case. (When drawn outward screens the eyes of observer 

 from the light. When not in use lies superimposed upon the circular prism 

 case.) V, Telescoping camera-tube in position for examination. V, Opening in 

 prism case, admitting light for illumination of color-prism. (The white glass 

 disk of prism is seen inside.) W, White glass of blood-pipette. X, Pipette 

 clamp held in position on the stage by grooves and guides. Y, Detachable 

 candleholder. Z, Rectangular opening in edge of case for reading haemoglobin 

 percentage indicated by beveled blade. 



The lower figure is the color-prism. E, Prism of colored glass. F, Semicircle 

 of white glass, the edge carrying the index haemoglobin percentage etched and 

 filled, in with black. G, Hole in which hub is fixed with rubber washers. 

 (Pivots in center of case hold the prism firmly in place.) H, Index of haemoglobin 

 percentage etched in black. /, Disk of white glass which serves the same 

 purpose as in the blood-pipette, breaks the glare of direct light, and furnishes a 

 white background to view the shades of color. 



3. Besides the support for the glass wedge and frame, there is 

 a white plaster mirror (M) which furnishes the diffused light 

 required in the test. 



4. The capillary tubes are carefully prepared to hold the 

 proper quantity of blood. The size of these tubes varies, and on 

 the handle of each is stamped a number indicating its capacity. 



