602 



BACTERIOLOGY. 



are similar to those of the preceding apparatus, but the 

 circular form of the apparatus admits of more exactness 

 when counting colonies on a circular plate.' 



Pakes ^ has introduced a cheap and convenient modi- 

 fication of Lafar's apparatus. It consists of a sheet of 

 white paper on which is printed a black disk ruled 



FlO. 106. 

 16 A 1 



Pakes's apparatus for counting colonies (reduced one-third). 



with white lines, in somewhat the same fashion as is 

 Lafar's counter, though the areas of the smallest sub- 

 divisions are not of one size and do not bear a constant 



^ Lafar's apparatus is to be obtained from F. MoUenkopf, 10 Thor- 

 strasse, Stuttgart, who holds the patent for it. Its price is about 8 

 marks. 



^ Journal of Bacteriology and Pathology, 1896, vol. iv. No. 1, 



