758 



A TEXT-BOOK OF BOTANY. 



for use. These solutions, as well as other reagents that are prone 

 to decomposition, may, however, be kept for months or even years 

 by preparing them with care and keeping them in a special kind 

 of bottle (Fig. 418). An ordinary bottle may be used, and is 

 fitted with a rubber stopper perforated so as to allow the intro- 

 duction of two glass tubes. These tubes are bent twice at right 

 angles and the free ends directed downwards. One of the tubes 

 is connected with an atomizer bulb and serves for forcing out the 



FIG. 418. Reagent bottle for sterile solutions. 



liquid. A small plug of absorbent cotton is placed in the tube 

 at the point C, so as to filter the air. This may be improved by 

 blowing a bulb in the tube for holding the cotton. The bottle 

 should be sterilized before placing the solution in it, and the solu- 

 tion should be made by adding the dye to sterile water contained 

 in the bottle. The solution may be afterwards further sterilized 

 by means of steam if this should be found necessary, as in this 

 way only a perfectly sterile solution could be produced. 



