OF MICROSCOPIC OBJECTS. 201 
in-door aquarium. It is recommended that the jars ip 
which the plants of Chava are grown should be moved about 
as little as possible, as the long roots are very tender, and 
will not bear agitation. 
An object which is interesting to the microscopist, as 
well as the unscientific observer, is the growth of seeds, as it 
is often erroneously termed. A shaving of the outside of . 
the seed is taken and laid upon the glass slide; a thin 
glass cover is then placed upon it, and a drop of water 
applied to its edge. The water will gradually flow under 
the glass and reach the section of the seed, when transparent 
fibres will appear to spring out and “grow” for some 
minutes. This, however, is produced by the unfolding of a 
spiral formation in the cells, and, therefore, has really no 
similarity to the true growth. The seeds of the Salvias, 
Collomias, Senecio, Ruellia, &c., are well suited for the 
display of this curious sight. 
To watch the development of the spores of ferns, and the 
fertilization and products, Dr. Carpenter recommends the 
following mode of proceeding :—“ Let a frond of a fern, 
whose fructification is mature, be laid upon a piece of fine 
paper, with its spore-bearing surface downwards; in the 
course of a day or two this paper will be found to be covered 
with a very fine brownish dust, which consists of the dis- 
charged spores. This must be carefully collected, and 
should be spread upon the surface of a smoothed fragment 
of porous sandstone; the stone being placed in a saucer, 
the bottom of which is covered with water, and a glass 
tumbler being inverted over it, the requisite supply of 
moisture is insured, and the spores will germinate luxuriantly. 
Some of the prothallia soon advance beyond the rest; and 
at the time when the advanced ones have long ceased to 
produce antheridia, and bear abundance of archegonia, those | 
which have remained behind in their growth are beginning 
to be covered with antheridia. If the crop be now kept 
with little moisture for several weeks and then suddenly 
watered, a large number of antheridia and archegonia 
