142 The Botanical Gazette. (March, 
the red alge particularly as to the preservation of the cell 
structure. 
The writers have used one per cent. chrome alum ineither 
distilled water or sea water carefully filtered through sand, 
according to the different habitat, for about four years. The | 
alga, carefully selected and washed free from dirt and debris, 
have been placed in it at once and preserved in it until needed 
for examination. The cell structure is well preserved in all 
cases. Very little washing is needed afterwards to allow 
staining by any of the ordinary staining reagents. Gelatinous 
intercellular substances, whether soft or more cartilaginous, 
are rendered firm but not especially opaque by treatment with 
it. Cyanophycez, Chlorophycez, and Rhodophycez do very 
well indeed. Phaeophycez, almost without exception, att 
rendered brittle in a short time, but while this renders them 
troublesome to manage, yet specimens prepared _ in this way 
and soaked out in water are excellent for study by crushing 
methods. It is the intercellular substance that is rendered 
more than by any other of the media we have tried. 
The Chlorophycez lose all of their green, or nearly all 
The Cyanophyceze and Rhodophycee often retain consider 
able (especially if kept away from the light), generally atleast 
enough to assist materially in the examination of the chrom® 
should have at least the greater part of the alum removed by 
for ferns and for flowering plants, better in all cases tha ‘i 
strong alcohol commonly used, but probably not superior 
