OF MICROSCOPIC OBJECTS. 135 



require will not be out of place. The Vallisneria requires a tem- 

 perature not lower than 55 or 60, and even a higher degree 

 than this renders its growth quicker; and no great change must 

 take place : the more equable the temperature the more healthy 

 will the plant be. A glass jar should be taken, having an inch or 

 two of mould at the bottom, which must be pressed down closely, 

 and the plant must be set in this. Water must then be gently 

 poured in, so as not to disturb the mould. As this plant flou- 

 rishes best when the water is frequently changed, Mr. Quekett 

 recommends that the jar should be occasionally placed, under a 

 tap of water, and a very gentle stream allowed to fall into it for 

 several hours, by which means much of the confervoid growth 

 will be got rid of and the plant invigorated. The Anacharis may 

 be rooted in the earth like the Vallisneria, but a small detached 

 piece may be thrown into the jar of water and there left until 

 wanted. For months the " circulation " will be well shown by it, 

 and it will probably grow and increase. It is also very healthy in an 

 in-door aquarium. It is recommended that the jars in which any 

 of the Chara 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 erro- 

 neously 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 the edge of this. The 

 water will then gradually flow under the glass and reach the sec- 

 tion of the seed, when the 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 fer- 

 tilization 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-bear- 

 ing 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 



