76 CLINICAL MICROSCOPY AND DIAGNOSIS. 



Estimation of Haemoglobin. After arranging the 

 apparatus (Fleischl's) cover the bottom of one of the 

 cells with distilled water. Fill the capillary pipette 

 with blood, taking care not to soil its exterior, and to 

 have the tube just full. Rinse out the pipette in the 

 water of the cell, and by dropping on more distilled 

 water. Fill the cell almost full and with the handle of 

 the pipette thoroughly mix the contents of the cell. 

 Both cells are now carefully filled with water till both 

 present a convex surface. Using an oil or gas lamp, 

 (not daylight) compare the tint of the blood cell with 

 that of the standard bar under the water cell, moving 

 the bar till the two tints are the same. Read off the 

 percentage of normal on the bar index. 



Estimation of the Red Corpuscles. Carefully fill 

 the pipette of the haemacytometer up to 1 with blood. 

 At oiKje draw in dilution fluid till mark on bulb, 101, is 

 reached. Mix the blood and the fluid by twirling the 

 pipette between the fingers for a minute. After blow- 

 ing out the fluid that fills the tube of the pipette, place 

 a drop of the mixture in the bulb, on the centre of the 

 counting slide. Place over this a cover glass, taking 

 care not to allow the blood to, overflow the cell edges. 

 Examine under the microscope and finding the ruled 

 squares, count the red corpuscles on at least 40 squares. 

 This should be repeated several times and an average 

 taken. As each ruled square is -^^g c. mm. we can 

 readily calculate the number of corpuscles per c. 

 mm., by the following formula: 



