208 



PHYSIOLOGICAL CHEMISTRY. 



FIG. 64. 



FLEISCHL'S H^IMOMETER. 

 (Da Costa.) 



the base and stage of an ordinary microscope. Underneath the 

 stage is placed a colored glass wedge (see Fig. 66, p. 209), so 

 arranged as to run immediately beneath the glass bottom of one of 

 the compartments of the cylinder and ground in such a manner that 



each part of the wedge corresponds in 

 color to a solution of haemoglobin of 

 some definite percentage. The glass 

 wedge is held in a metal frame and 

 may be moved backward or forward 

 by means of a rack and pinion ar- 

 rangement. A scale along the side of 

 this frame indicates the percentage 

 of the normal amount of haemoglobin 

 which each particular variation in the 

 depth of color of the ground wedge 

 represents, taking the normal haemo- 

 globin content as loo. 1 In a position 

 corresponding to the position of the 

 mirror on the ordinary microscope is attached a light-colored opaque 

 plate which serves to reflect the light upward through the colored 

 wedge and the cylinder to the eye of the observer. 



In making a determination of the percentage of haemoglobin 

 by this instrument the procedure is as follows : Fill each compart- 

 ment about three-fourths full of distilled water. Puncture the 

 finger-tip or lobe of the ear of the subject by 

 means of a sterile needle or scalpel and, as soon 

 as a drop of blood appears, place one end of 

 the capillary pipette (Fig. 65), which accom- 

 panies the instrument, against the drop and 

 allow it to fill by capillary attraction. To prevent 

 the blood from adhering to the exterior of the 

 tube, and so render the determination inaccu- 

 rate, it is customary to apply a very thin coat- 

 ing of mutton fat to the outer surface before 



using or to wrap the tube in a piece of oily chamois when not in 

 use. As soon as the tube has been accurately filled with blood 

 it should be clipped into the water of one of the compartments of 

 the cylinder and all traces of the blood washed out with water by 

 means of a small dropper which accompanies the instrument. If 

 the blood is not well distributed throughout the compartment and 



1 The scale of the ordinary instrument is usually too high. 



FIG. 65. 



PIPETTE OF FLEISCHL'S 

 H^MOMETER. 



