• 25 - 
are not clear, the water may be drawn out gradually and replaced by the 
potassium hydrate, placing a drop of this solution at one side of the cover 
glass and a bit of absorbent paper at the other side to take up the water. 
Filter paper serves this purpose best. If the asci, spores and paraphyses 
do not come out distinctly with this treatment, the section may be carefully 
crushed after the character and color of the exciple or exciples, the hypothe- 
cium and the hymenium are all studied. Then if still unsuccessful, some 
stain may be applied. Iodine solution will serve to differentiate between the 
asci and the paraphyses as it stains them differently and often brings out 
the branching of the paraphyses beautifully. Some experince will enable 
the beginner to get just the best strength of iodine solution, but one grain of 
iodine, three grains of iodine Of potassium and one of pure water makes a 
very good combination. The sections are almost sure to be too thick at first, 
but experience will remedy this difficulty. The razor should be sharp enough 
to cut a section of the pith thin enough so that it will float in the air, and 
then the section of the lichen or lichen apothecium will be so thin that one 
will often need to place his slide on white paper in order to see the sections, 
which are to be transferred from the razor to the slide by means of a small 
camel’s hair or other similar brush. To insert the material to be sectioned 
into the pith, cut a slit through a radius of the pith from one end down an 
inch or more. Then taking a portion of thallus or fruit 2 or 3 mm. across, 
insert into the opening in such away as to be able to cut in the direction 
desired. If the fruit is larger than 3 mm. in diameter, it is still best not 
to try to cut larger sections, but an edge of the apothecium is to be included 
in the section, and it is permissible to section one whole, cutting through a 
diameter so as to see the structure. However, this section is likely to be of 
little use for any careful work. Do not attempt to cut all the way across the 
pith at every cut, but rather to get very thin sections of small portions of the 
upper surface of the pith, including a section of part or all of the lichen struc- 
ture to be studied. This procedure will soon render the upper surface of the 
pith uneven, when a complete section may be taken to level it. Many begin- 
ners will not think all of this advice necessary; but all will appreciate it 
after a few trials, and will wish it were possible to make matters much 
plainer than can possibly be done in any written directions. As to the 
razor, it must be of good quality, not too thick, and is better if hollow ground 
on one side only. Then keep it sharp, sharp! sharp!! Do not sharpen a 
moment and then resume work with a contented air, but see if it will readily 
cut sections of pith that are scarcely visible when floating in the air. If not, 
it is not in condition for cutting sections of lichens. Then there should be 
always at hand on the table a metric rule, for the larger measurements of 
thalli and fruits, which of course can not be made with the micrometer. 
There are many other things that might be stated, but too much is con- 
fusing to the beginner. At first, throw away unfruited specimens, unless you 
have material with which to compare, but later, after you know something 
of lichen species and think you have a sterile one different from any of the 
fertile ones, determine it or sent to an expert. If you have no microscope, 
you can still do some good work with fifty or one hundred authentic speci- 
