CHEMICAL PHYSIOLOGY. 



(6.) Puncture a finger near the root of the nail with the 

 lancet projecting from (F), and with the pipette (B) suck 

 up 5 c.mm. of the blood, and blow it into the diluting solu- 

 tion, and mix the two with the stirrer (E). 



Fig. 2. Gowers' Hsemocytometer. A, Pipette for measuring the diluting 

 solution ; B, for measuring the blood ; C, cell with divisions on the 

 floor, mounted on a slide, to which springs are fixed to secure the 

 cover glass ; D, vessel in which the solution is made ; E, spud for 

 mixing the blood and solution ; F, guarded spear-pointed needle. 



(c.) Place a drop of the mixture on the centre of the glass 

 cell (C), see that it exactly fills the cell, and cover it gently 

 with the cover-glass, securing the latter with the two springs. 

 Place the cell with its plate on the stage of a microscope, 

 and focus for the squares ruled 011 its base. 



(d.) When the corpuscles have subsided, count the 

 number in 10 squares, and this, when multiplied by 10,000, 

 gives the number in a cubic millimetre of blood 



(e.) Wash the instrument, and in cleaning the cell do 

 this with a stream of distilled water from a wash-bottle. 



