xperiment has been successful, at the end
of this time the spore membrane will have burst, and the contents
escaped in the form of a naked mass of protoplasm (Zooespore) with a
nucleus, and often showing a vacuole (Fig. 5, _v_), that
alternately becomes much distended, and then disappears entirely. On
first escaping it is usually provided with a long, whip-like
filament of protoplasm, which is in active movement, and by means of
which the cell swims actively through the water (Fig. 5, _I_ i).
Sometimes such a cell will be seen to divide into two, the process
taking but a short time, so that the numbers of these cells under
favorable conditions may become very large. After a time the lash is
withdrawn, and the cell assumes much the form of a small amoeba (_I_
ii).

The succeeding stages are difficult to follow. After repeatedly
dividing, a large number of these amoeba-like cells run together,
coalescing when they come in contact, and forming a mass of protoplasm
that grows, and finally assumes the form from which it started.

Of the common forms of slime moulds the species of _Trichia_ (Figs.
_D_, _I_) and _Physarum_ are, perhaps, the best for studying the
germination, as the spores are larger than in most other forms, and
germinate more readily. The experiment is apt to be most successful
if the spores are sown in a drop of water in which has been infused
some vegetable matter, such as a bit of rotten wood, boiling
thoroughly to kill all germs. A drop of this fluid should be placed
on a perfectly clean cover glass, which it is well to pass once or
twice through a flame, and the spores transferred to this drop with
a needle previously heated. By these precautions foreign germs will
be avoided, which otherwise may interfere seriously with the growth
of the young slime moulds. After sowing the spores in the drop of
culture fluid, the whole should be inverted over a so-called "moist
chamber." This is simply a square of thick blotting paper, in which
an opening is cut small enough to be entirely covered by the cover
glass, but large enough so that the drop in the centre of the cover
glass will not touch the sides of the chamber, but will hang
suspended clear in it. The blotting paper should be soaked
thoroughly in pure water (distilled water is preferable), and then
placed on a slide, covering carefully with the cover glass with the
suspended drop of fluid c