120 BACTERIA IN RELATION TO PLANT DISEASES. 
at the left: Xylol, second xylol, xylol one-third absolute alcohol two-thirds, 95 per 
cent alcohol, 75 per cent alcohol, 55 per cent alcohol, 40 per cent alcohol, carbol- 
fuchsin, 40 per cent alcohol, second 40 per cent alcohol, 55. per cent alcohol, 65 -per 
cent alcohol, 75 per cent alcohol, 95 per cent alcohol, absolute alcohol, second 
absolute alcohol, xylol, second xylol. From. this last jar the material is mounted 
in balsam. Turpentine may be substituted for xylol in jars 1 and 2. After the 
paraffin is fully removed, the slides are passed rapidly from jar to jar (a minute or two 
in each being generally 
sufficient) until the stain 
is reached. After remain- 
ing in the stain the proper 
length of time (usually 
three to ten minutes, but 
sometimes much longer) 
the slides usually are 
allowed to remain in the 
40 per cent alcohols for a 
number of minutes, with 
frequentinspection. When 
they appear to be properly 
bleached (rather pale) they 
are passed rapidly through 
the remaining jars until 
they ‘reach the xylol, in 
which they may remain 
for some time without 
injury, if they can not’ be 
they must not be allowed 
to stand for any great 
length of time in any of 
the alcohols. ‘The secret 
of success lies in obtain- 
ing just the proper amount 
of differentiation in. the 
40 per cent alcohol and in 
not losing any of this later 
ou, To retain the stain it 
is necessary sometimes to omit some-of the graded alcohols. 
The time required for properly staining sections varies from one or two minutes 
to a half day or more, according to the subject and the stain employed. No general 
rule applicable to all cases can be given. When the material is selected for embed- 
ding, its serial number, with a full description, is entered in the record book (fig. 112). 
Fig. 108.* 
*Fic, 108—One of a series of drawers divided into small compartments for holding infiltrated, 
embedded material, cut and uncut. 
mounted immediately, but 
