MYXOMYCETES AND SCHIZOPHYTES 
165 
which the material may be pinned. For most purposes, the specimens 
are simply allowed to dry, and are then fastened with glue or paste to 
the bottom of a small box. 
Plasmodia and young sporangia may be fixed in chromo-acetic 
acid or Flemming’s fluid. Sections are easily cut in paraffin, and 
should not be more than 5 ju in thickness; for nuclear details, sections 
should not be thicker than 3 /jl. The safranin, gentian-violet, orange 
combination is good for a study of the general development and for 
some cytological features, but iron-alum haematoxylin is better for 
nuclear details. 
Spores of most myxomycetes will germinate as soon as they are 
thoroughly ripe, and, during the first year, germination is more prompt 
than in case of older spores. Fresh spores may germinate in half 
an hour; the time may extend to several hours; spores two or three 
years old may germinate in three or four days, or may not germinate 
at all. We have never succeeded in germinating spores which were 
more than three years old. The longevity is doubtless different 
in different species. In most cases, spores will germinate in water, 
if they will germinate at all. For small cultures, the hanging-drop 
method, described on page 77, may be used. 
Plasmodia may be raised by sowing spores on moist, rotten bark 
or wood and placing the culture under a bell jar, where the moist, 
sultry condition favorable to their growth is easily imitated. Plas¬ 
modia may be got upon the slide by inclining the slide at an angle of 
about 15°, with one end of the slide at the edge of the plasmodium, 
and allowing water to flow very gently down from the upper end of 
the slide to the lower. The proper flow of water could be secured 
by dropping water from a pipette, but a less tedious plan is to arrange 
a siphon so as to secure a similar current. The plasmodium will 
creep up the slide against the current, furnishing an excellent illus¬ 
tration of rheotropism. Enough plasmodium for an illustration may 
be formed in two or three hours. Examined under the microscope, 
the preparation should give an excellent view of the streaming 
movements of protoplasm. 
The following is another method for getting the plasmodia upon 
the slide: Place the slides upon a pane of glass and upon each slide 
place a small piece of plasmodium-bearing wood. Cover with a bell 
jar. Wet blotting paper or a small dish of water included under the 
jar will help to create the warm, sultry atmosphere necessary. The 
