METHODS OF EXAMINATION 



Fig. 1. The Thoma hematooytometer. 



disc which is thinner than the surrounding plate. The distance 

 from the top of the disc to the under surface of a cover glass placed 

 on the plate is exactly 0.1 millimeter. The upper surface of the 

 disc is ruled as shown in Fig. 2. The central square is ruled with 

 lines aV mm - apart giving 400 squares each containing T — sq. mm. 



Fh;. 3. Thoma, central rulinsi. 



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 ■ignis iiii iiii mi iiiiuwws 

 ■iliiiH iiij iiii liii liiiilWHiB 

 ■niWBiJii iiii iiii liiiaiBinn 



iinni§ iiii iiii iiii iii _ 



ifl 1 iiii iiii iiiiBipiii 



Sm iiii iiii iiii iiiiniwwn 

 m iiii iiii iiii iiiiwuniH 



Fio. •">. t urck. 

 Rulings of Counting Chambers. 



