44 



PRACTICAL PHYSIOLOGY. 



[VI. 



its floor "divided' into squares ^o mm., in which the blood-corpuscles 

 are counted r 



(/.) Tbe diluting solution consists of a solution of sodic sulphate 



in distilled yatersp. gr. 1025. 



2. Mcde, pf Using the Instrument. 



(a.) By*raearla<)f the pipette (A) place 995 c.mm. the dilut- 

 ing solution" in the mixing jar (D). 



(/;.) Puncture a finger near the root of the nail with the lancet 

 projecting fronv (F), and with the pipette (B) suck up 5 c.mm. of 



FlG. 20. Gowers' HEemocytometer. 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. 



the blood, and blow it into the diluting solution, and mix the two 

 with the stirrer (E). 



(r,.) 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 on its base. 



(d.} When the corpuscles have subsided, count the number in 

 ten squares, and this, when multiplied by 10,000, gives the number 

 in a cubic millimetre of blood. 



