134 PRACTICAL BACTERIOLOGY. 



with aqueous solution of methylene blue, which will 

 stain the rodlets blue, whilst the spores remain red. 



In this manner rodlets and spores can be exceed- 

 ingly well seen. It is best to use colours that con- 

 trast well with one another. Five per cent, sulphuric 

 or nitric acid may also be used for decolourisation, but 

 they require much greater care on account of their 

 powerful action. 



The same difference of capacity in absorbing and 

 retaining staining reagents is manifested by the 

 sp'ores as by the vegetative cells, only in a much less 

 degree. On this account the student must find out by 

 experiment the best method for staining the various 

 species. 



