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REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 23
of rock-weed. For mounting the smaller species one-should have two or three shallow
dishes of salt water, in which the plants are to be washed and floated out, and a
deep basin of either salt or fresh water, as the case may be, for mounting. A zinc
tank, one of whose sides is slanting, is convenient for mounting, but is rather an
awkward thing to carry about in travelling. The specimens to be mounted are put
into the basin and floated out; a piece of paper is slipped under them and they are
lifted out of the water. A moderately thick unglazed paper is best for mounting,
although almost any kind will do, provided it is not very thin. Many ladies make use
of photographers cards.
With a little practice it is perfectly easy to remove sea-weeds from the water, but to
prevent the specimen slipping off the paper or to one side of the paper it is best to
put the middle finger under the center of the paper and raise it so that the water
drains off equally on all sides. Some slip a pane of glass under the paper, and lift it
out of the water in that way. The papers should then be left in an inclined position
for a short time, so that the superfluous water may run off. They are then to be put
on the driers and covered with a piece of muslin or other thin white cloth, from
which the glazing has been removed by washing. Very gelatinous specimens should
be exposed for some time to the air before pressing. The driers should be of bibulous
paper and the best material, but unfortunately the most expensive, is thick white
blotting-paper. The specimens are to be laid on the paper and covered with a cloth,
and then another layer of paper is placed above, and so on. The best form of press is
a board with a number of stones for weights. The driers should be changed morning
and night until the specimens are dry. Some of the smaller species dry in a few
hours; others require two or three days. Great pressure is to be avoided, and the
specimens, if prepared in fresh water, should not be allowed to remain long in the
water. Most small species adhere to the papers naturally; others require to be
fastened with gum. Besides mounting specimens on paper, it is a very good plan to
prepare specimens of fruit or any small filamentous species on pieces of mica or
glass. Fragments of mica good enough for the purpose can be obtained for a very
small sum of those who manufacture air-tight stoves. Specimens prepared on mica
can be moistened and at once used for microscopic study. All really microscopic
forms, such as Glœocapsa, Clathrocystis, &c., had better be mounted on mica or
glass than on paper. A difficulty is experienced in preparing corallines and other
calcareous forms. If prepared in the same way as other sea-weeds, they become very
brittle, and are often ruined by transportation. Various means have been devised for
making them less brittle—such as painting them with a thin solution of gum. A
better method is to paint them with a hot solution of isinglass which has been boiled
for a few moments in alcohol. The habit may be preserved, although the structure is
somewhat injured, by immersing corallines