TIME SAVING BACTERIOLOGICAL APPARATUS 563 



with agar as with gelatin. The value of this apparatus is especi- 

 ally noticeable with a stiff agar (2.5 per cent), used in such 

 medium as Endo's agar. With the old methods of clarification 

 the nitration of such stiff agar was a task. 



APPARATUS FOR WASHING 



The washing of large quantities of test tubes and other appa- 

 ratus by hand is time consuming and expensive. The high cost 

 of laboratory apparatus makes it imperative that test tubes 

 be cleaned and sterilized as soon as possible in order that they 

 may not be out of use for any extended period of time. We 

 resorted to the use of the contrivance which is used with success 

 in the carbonated drink industry and while it is not directly 

 suited to all bacteriological apparatus, it is serving well its 

 purpose. This apparatus consists of a revolving brush attached 

 to the shaft of an electric motor. Figures 4, 5 and 6 show the 

 general construction of this apparatus. Those in figures 4 and 5 

 are driven by an electric motor while that in figure 6 is driven 

 by a water motor. Figures 5 and 6 are equipped with a contriv- 

 ance to admit clean water into the test tube or the bottle while 

 it is being washed by the revolving brush. Any size brush can 

 be attached to the shaft. 



In our experience we find that the simple machine shown in 

 figure 4 is as satisfactory as those with the contrivance for 

 admitting water. If these machines are run carefully, breakage 

 of glass ware is a negligible factor with any of them. 



