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CLINICAL BACTERIOLOGY AND HiEMATOLOGY 



In practice it is simplest to take the top one, and all the others 

 that have a double ruling; when you have counted these you 

 will have counted five rows of twenty each at equal dis- 

 tances from one another, which will give you a very fair 

 average. (See Fig. 48, where the bars which are to be 

 counted are shaded.) 



V 



FIG. 48. THE "BARS" WHICH ARE TO BE COUNTED ARE SHADED. 



In counting these bars count all the corpuscles which are 

 lying on or touching the top line, as in the bar you are count- 

 ing, also those which are lying on or touching the extreme 

 left-hand limit of the bar. Exclude those on or touching the 

 lower and right-hand lines. The reason for this will appear 

 subsequently. 



This is the most convenient way when you have no 



