275 



The Estimation of the Haemoglobin 



Gower's haemoglobinometer is the simplest 

 and best. In sucking up the blood take care not 

 to hold the tube too vertical, as the blood readily 

 flows out from the rather large calibre of the tube. 

 Order from a good maker, as several inferior 

 instruments are on the market. The round form 

 of tube is more easy to manipulate than' the flat. 



The standard of comparison in this apparatus 

 is pikro-carmine gelatine, the colour of which 

 corresponds to a one per cent, watery solution 

 of normal blood. 



All blood counting apparatus, etc., can be 

 got from ' T. Hawskley, 357 Oxford Street, 

 London, W. 



Dare's haemoglobinometer is accurate. It 

 possesses the advantage of dispensing with a 

 pipette. It costs £^. 



To Count Platelets 



Diluting fluid : glycerine saturated with 

 dahlia, and two per cent, saline solution, take 

 equal parts of these. 



Or better, a freshly-made live per cent, solution in water 

 of crystallized sodium metaphosphate. Dilute the exuding 

 drop of blood with live to ten times its bulk of fluid. The 

 exact amount need not be known. Count the ratio of platelets 

 to red cells in an ordinary coverglass preparation. 



The ratio of, platelets to red cells is 1:8 about. 

 The absolute value per mm.' 635,000 about. 



Differential Counting of Leucocytes (vide 

 page 41). 



