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 the edge of this. The water will then gradually flow under the glass and reach the section 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 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 discharged 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 simultaneously open, and in a few hours afterwards the surface of the larger prothallia will be found almost covered with moving antherozoids. Such prothallia as exhibit freshly opened archegonia are now to be held by one lobe between the forefinger and thumb of the left hand, so that the upper surface of the prothallium lies upon the thumb; and the thinnest possible sections are then to be made with a narrow-bladed knife perpendicularly to the surface of the prothallium. Of these sections, which after much practice may be made no more than 1-15th of a line of thickness, some will probably lay open the canals of the archegonia, and within these, when examined with a power of 200 or 300 diameters, antherozoids may be occasionally distinguished.”