OF MICROSCOPIC OBJECTS. 201 



in-door aquarium. It is recommended that the jars ia 

 which the plants of 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 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 curions 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 



