60 



MICROBIOLOGY 



ing apparatus such as the Chamber-land or Berkefeld 

 bougies that will remove bacteria. There is a large variety 

 of these on the market and one must determine the size and 

 kind best adapted for the work in hand. The Berkefeld 

 bougies are made from infusorial earth and are more porous 

 than the Pasteur filter or Chamberland bougies. They are 



Fig. 26. Fig, 27. 



Fig. 26. Eclipse autoclave for rapid sterilization under steam 

 pressure. 



Fig. 27. Arnold's steam sterilizer. (Board of Health pattern.) 



graded according to the fineness of the pores as A., B., C., 

 etc. 



In making plate cultures, it is necessary to have accu- 

 rately levelled shelves on which to stand the plates or to use 

 a levelling apparatus. This is very important where the 

 exact number of colonies is to be determined. 



There is a large variety of pipettes, graduates, beakers, 

 dessicators, etc., that are useful in special kinds of work. 



Apparatus for making vaccines. For this work, in 

 addition to the ordinary apparatus, especially designed 



