STAINING, PRACTICAL AND THEORETICAL 



14. Clear in xylol. 



15. Mount in D.P.X. or Clearmount or Michrome mountant. 



Technique III 



For chamber-counting 



1. A 1:10 mixture of the blood with the counting fluid (solu- 

 tion F) is made by measuring one volume of blood with a standard 

 blood pipette and discharging into nine volumes of solution F, 

 measured by a " Carlberg " micropipette, in an 8 x 70 mm. tube. 



2. Shake the tube by hand until the diluted blood becomes 

 clear, indicating complete haemolysis of the red cells. 



3. Immediately fill counting chambers in the usual way. 



4. Allow the counting chambers to stand in a damp container 

 for at least five minutes to permit the white cells to settle. 



5. To facilitate identification of the basophil, use a blue filter 

 in the microscope lamp. 



Results: 



Basophil leucocytes are stained metachromatically, their gran- 

 ules being purplish red, while their nuclei as well as all other 

 leucocytes and tissue components are stained faintly. 



Notes: 



{a) Human venous or capillary blood and rabbit venous blood 

 as well as rabbit tissues were used by the authors. 



{b) Jessen counting chambers with 0-4 mm. depth and o*i ml. 

 volume were used for counting human basophils. In all other 

 cases Fuchs-Rosenthal counting chambers with 0-2 mm. depth 

 and 3*2 mm.^ volume were used. 



(c) In smears of human blood, the authors found that the 

 average diameter of the basophil leucocytes was io-2±o-2jLi 

 (7-iija), while that of the rabbit was io-8±o-3)a (5-4-8-o/x). 



{d) The technique is recommended by the author (Boseila) for 

 routine use in haematological laboratories, in the belief that the 

 simple methods described may help to throw more light on the 

 unsettled problem of the role played by the basophil leucocyte in 

 health and disease. The use of micropipettes instead of the 

 commonly used standard leucocyte diluting pipettes offers the 

 advantages of economy in the cost of apparatus and more accurate 



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