32 
PREPARATIONS OF LICHENS. 
the pursuit of the study. Admirable sets of specimens, carefully 
determined by highly competent authorities, have been issued, and 
an excellent Lichen Flora has reached its third edition. That such 
a special scientific volume as Leighton’s Lichen Flora should have 
reached a third edition, is a welcome surprise, and is, in itself, an 
evidence that the study of Lichenology must be extending. Another 
important aid to the prosecution of this study was noticed in our 
last number, which we advert to again, namely, the issue by Mr. W. 
Joshua, of Cirencester, of a series of microscopical mountings of 
Lichens, some of which it has now been our privilege to examine. 
There are three requisites which we contend that such a series 
should possess to ensure their complete success. They should be 
critically accurate in their determination. The series should be 
a thoroughly representative one, containing all the principal types ; 
and the parts of such specimens selected for mounting should be 
those which are essential for educational purposes. To these we 
might add a fourth in the suggestion that the manipulation should 
be unimpeachable. As far as we have seen, we have every reason 
to believe that this series to which we allude, fulfils all these four 
conditions. Mr. Joshua is an old and experienced Lichenologist, 
enjoying the friendship and counsel of the best Lichenologists in 
the kingdom, and hence there is no room for doubt of the first 
condition being fulfilled. The list which we published of the species 
illustrated in the first portion of the .series, will afford ample proof 
how the second condition is in course of fulfilment. An examina- 
tion of some of the “ slides ” already issued, enable us to testify 
that the third and fourth conditions are satisfied as fully as the first 
and second. We have doubts whether any biologist can sit down 
to such mountings as those of Licliina pygmea, Pyrenopsis granatina , 
Collema biatorinam , Collema multipartitum and Omphalaria pulvi- 
nata , without profound interest, and deep thoughtfulness being 
produced by their examination. Of course the dual hypothesis 
will come into one’s mind, but thoughts and reflections far higher 
than such an hypothesis will soon crowd that into the background. 
There are, perhaps, three classes of individuals to whom these 
preparations will be welcome. There are the Lichenologists, or 
those ambitious of becoming such, who would study them as illus- 
trations of genera and species, and they will be glad to have just 
what they require prepared for their use, without all the labour and 
the many failures of inexperience, perhaps, or at least without a 
great expenditure of time necessary to make such preparations. 
Then there are the general students of biology, who are neither 
mycologists or lichenologists, but who desire to see and learn some- 
thing of the structure of all the lower orders of plants. Of course 
such persons will have to depend for their best help on such series 
as the present, and those of a kindred nature in other orders. 
Finally, there are the curious, who want to see and possess new 
objects, rare, beautiful, and true. To them it matters little what 
they are called, so long as they are curious, or beautiful, or 
