156 



BACTERIOLOGICAL DIAGNOSIS. 



degree of dilution. The other is graduated into a 

 hundred parts, the graduation being such that when 

 20 cubic millimetres of normal blood are diluted with 

 water up to the 100 mark the colour of the two tubes 

 should be exactly the same. A pipette measuring 20 

 c.m. and a dropping bottle (which is to be filled with 

 water) are also provided. 



Method of use. Place a few drops of water (preferably, 

 but not necessarily, distilled) in the graduated tube. 



FIG. 26. Govvers' Haemoglobinometer. 



Draw the blood in the usual w r ay. Apply the tip of the 

 measuring pipette to the drop and suck gently until the 

 blood reaches up to the mark. Now put the tip of the 

 pipette into the small quantity of water in the bottom 

 of the graduated tube and blow out the blood ; suck 

 water up the pipette until it reaches above the mark 

 and blow it out ; repeat this process until the blood is 

 thoroughly washed out from the tube. 



Place the two tubes side by side on a sheet of white 

 paper in front of a well-lighted window which is not 



