Z THE MICROSCOPICAL NEWS. 
Society sending in a report of the meetings ; we shall be glad to find 
space amongst the Notes and Queries for such communications, 
but as we are anxious to increase the value of this last department, 
it has become necessary to curtail the’Notices of Meetings. 
Amongst the “innocents” our last page must succumb. ‘The 
Notes and Queries will absorb this also, as in order to increase the 
space at our disposal we have decided to reply to correspondents 
through the post, and to abolish the Sale and Exchange Columns. 
The few exchanges which have come in during the past month 
have been placed amongst the Notes and Queries, in order that 
the senders may not be disappointed. 
We are glad to state that the sale of the Journal has improved 
during the past year, and as the present changes are the outcome 
of the expressed opinions of many correspondents, we trust they 
will meet with the approval of our readers, and so lead to the con- 
tinued extension of the circulation. 
PLANT “CRYSTAQES: 
Dr. ASER POLI. 
FTER Malpighi, who was the first to discover the existence of 
Plant Crystals, the principal names connected with this sub- 
ject are Sanis, Holzner, and Gulliver, but the works of the last 
mentioned, though containing many important observations, are 
very little known. 
These crystals may be roughly divided into two classes, viz. : 
those which are composed of calcium oxalate, and those which are 
not; the former class being distinguishable from the latter by their 
insolubility in water and acetic acid. Crystals of calcium carbon- 
ate and sulphate do not occur in plants. 
Calcium oxalate crystallizes in two systems—in the tetragonal 
with three molecules of water, and in the monoclinic with one 
molecule of water. The octahedrons (as crystals of Begonia, Tra- 
descantia, &c.), are generally tetragonal, while the short prismatic 
crystals, the raphides, and all those crystals which were formerly 
believed to be sulphate of calcium (as the long prismatic crystals 
of Iris) are monoclinic. 
Gulliver distinguished four principal forms of plant crystals,— 
raphides, sphzraphides (drusen of the Germans), short prismatic 
crystals, and long prismatic crystals. Of these the first are frequent 
in Mono-cotyledons, and occur also in some Dicotyledons. They 
are found in Vitacesze, Balsaminaces, Galiaceee, and Onagraceze, 
while in the British Exogens their presence is so confined to the 
last three orders as to form one of their characteristics. Hydrangea 
