COUNTING APPARATUS 9 
being done, the sample of food should be thoroughly agitated on a 
shaking machine with glass beads or broken glass. 
Fig. 7.—Wolffhuegel Counting Apparatus. 
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Fie. 8.—Types of Counting Devices. 
A, Petri Dish with the Bottom Divided into Squares; B, Lafar’s Counting Plate; C and D, 
Roszahegyi’s Counting Flask; Z, Jeffer’s Counting Plate. 
Pouring of Plates. A series of these should be poured with different 
concentrations of the sample. These may be obtained by thoroughly 
shaking a portion of the sample in sterile water and transferring a loop 
