14 THE AMERICAN MONTHLY | [Jan 
ordinary cover-glass may be used, by cementing it to a me- 
tallic ring of proper size, and when-firmly fixed, punch a 
hole through the center. Smooth the edge of the hole with 
a round file. Small irregularities will not be visible when 
the cell is filled with mounting medium. Another plan is to 
wet the cover-glass with a little saliva, and press it down on 
the center of the turn-table. Set the plate to revolving, and 
touch the surface of the glass with a writing diamond. With 
a little practice, this is by far the neatest and most expedi- 
tious way.— National Druggist. 
NuMBER OF SpEcIES oF PLants.—Professor 8. H. Vines, 
in his opening address to the Botanical Section of the British 
Association at Bradford, gave some interesting figures ‘as to 
the number of species of plants at present known. ‘The fig- 
ures may be tabulated as follows : 
SPECIES OF PLANTS. 
{ Dicotyledons 78,200 
| Monocotyledons 19,600 
- Phanerogams { Gymnosperms 2,420 
| 100,220 
Subsequent additions 5,011 
105,231 
( Filicine (including Isoetes) 
about. 3,000 
Pteridophyta Lycopodine, about 432 
Eqisitine about 20 
3,452 
Musci 4,609 
Bryophyta Hepatice 3,041 
7,650 
Fungi, (including Bacteria) 39,663 
Lichens 5,600 
Thallophyta Algz (including 6000 Diatoms)  14,0u0 
59,263 
Making a grand total of... 2... cece eee eee ees 175,596 
which,when compared with the 10,000 species of plants known 
