148 PRACTICAL BACTERIOLOGY. 



firmly dowa upon the slide and to leave them there to 

 dry. When the section is absolutely dry, a small drop 

 of xylol is placed upon it, in order to preserve it from 

 the air; after it is quite saturated with the xylol, 

 it is wiped; a suflBciently large drop of Canada 

 balsam is placed upon it, and the cover-glass is put 

 on. Here again the spirit varnish is used after the 

 balsam is quite dry. The best plan, however, is to 

 dehydrate the sections by repeated immersions in 

 aniline oil. The colours are unaffected by this reagent, 

 and yet the section is soon completely freed from 

 water. The aniline oil must be frequently changed, 

 and then when the sections are quite dry, they are 

 treated as before with xylol, before they are imbedded 

 in Canada balsam. 



The preparations must be accurately labelled. 

 English slides are the best for this purpose, as they 

 afford space for a label at each end. At the one end 

 the name of the organism, the origin (section through 

 a lung, pure culture, etc.), and the date may be 

 entered; and at the other, the method of preparation 

 used. Special cabinets for containing slides may be 

 obtained. 



