1896,] Aqueous Media for Preserving Alge. 143 
chrome alum, the chromatophores, pyrenoids, nuclei and pro- 
toplasmic sac and threads showing very well indeed. Speci- 
mens kept in a cork-stoppered bottle in chrome alum showed 
avery distinct dark steel-blue stain affecting the nucleolus 
most, the nucleus and the chromatophores, and this remained 
after washing in water, dehydrating, and mounting in Canada 
With chrome alum, as well as all other preserving media, 
a fairly large Proportion of fluid should be used. 
Formalin. 
_ Formalin, formalose, or 40 per cent. formaldehyde, accord- 
ing to the trade name, has in the last two years become very 
Popular with both zoologists and botanists. It is not neces- 
sary for us to go into the literature, but we have found that 
= Per cent. solution of the formalin (1-2" formalin 
ln 99-98" distilled water or sea water) makes a solution 
sufficiently Powerful to kill, fix, and preserve any ordinary 
vegetable tissue. While the color fades more rapidly than 
'S May tend to alter the cell-contents or the intercellu- 
Years thie ; slightly, but in preparations kept for nearly two 
le, = Not sufficiently marked to be especially noticea- 
fungi oe iD the same percentages works excellently for 
their 2a the higher plants. Toadstools are preserved in 
cord; ae Shapes and in more or less of their natural colors 
"§ to the species, 
c Camphor water. 
tion jg peor-gum is sparingly soluble in water, but the solu- 
Phorateq Prejudicial to the life of microorganisms. Cam- 
ve b Water is very useful when considerable collections 
fen made and cannot be examined for several hours. 
