Algae of all kinds are best preserved by adding to the water in which they are living an equal volume of a weak solution (about of potassium acetate (to which has been added a minute quantity of cupric acetate). They may also be preserved by adding a few crystals of carbolic acid to the ﬂuid containing them (about six or eight grains of crystallized carbolic acid to each ounce of liquid), but the outlines of the cells have not the clearness shown by those preserved in potassium acetate. Most algae are much better for examination when preserved in a ﬂuid medium than when dried. On drying they usually collapse, and on being soaked out they very often do not reattain their original torm. Most of the Myxophyceae, however, can be preserved very well by drying, and at the same time they retain their bright colours, this being a distinct advantage over those preserved in ﬂuid.