METHODS OF PEESERVATION 141 
METHODS OF PRESERVATION 
Where cell characters are among the chief requisites for the 
determination of species, as is the case with many of these plants, 
specimens preserved on paper, according to the usual method with 
seaweeds, are, to say the least, extremely unsatisfactory. Indeed, 
one is sometimes tempted to discard such methods altogether. 
Nevertheless, this method is, in certain respects, of considerable 
value, and should be generally, though not exclusively employed ; 
paper or mica mounts are most convenient for the herbarium to 
show distribution and form in the mass ; furthermore, they furnish 
a record which is likely to be permanent, while slide mounts are 
more liable to deterioration or accidental injury. 
For purposes of accurate study, however, and for convenience 
of comparison of a large number of specimens, it is necessary to 
have material fixed and mounted on slides, or at least preserved 
in bottles. Of the more elaborate methods, we have attained 
greatest success by fixation in Flemming’s stronger solution, fol- 
lowed by staining in iron haematoxylin, with the addition of a 
light counter-stain of Congo red. Great care is necessary to pre- 
vent plasmolysis and distortion.* This method requires too much 
time if one desires a large series of one species for comparative 
study. 
The following simple method has proved of great service ; 
enough material for two or three mounts is dropped into a small 
bottle of Flemming’s stronger solution for a few seconds or 
moments (the length of time varying with the delicacy of the 
species), then rinsed hastily, arranged on slides, and covered with 
a few drops of two to five per cent. solution of chromic alum ; the 
cover-glass is laid on, the superfluous fluid removed with filter or 
blotting paper, and the mount sealed with colorless marine glue. 
Preparations made in this manner are somewhat liable to deteri- 
oration because of defective sealing, but enough mounts may 
* The most useful discussion of this and similar methods is to be found in the articles 
C. J. Chamberlain, Journ. Applied Mic. 1: 156. 1898; 2: 506, 543. 1899, and 
SO more regen work of F. a von Wellheim, Zur معيو‎ os Süsswas- 
ہمت‎ Jah wiss. Bot. 212 1894, and Beiträge zur Fixirung und 
Präparation geo Pests. Oes Bot. Zeit. 48: 53-59, 99-105. 1898. 
(Translation in Bull. Soc. Belg. de va 24: 22-103. 1898.) See also a note by 
Charles Thom, Bot. Gaz. 24: 273. 1897. 
