The Vallisneria requires to be cut in sections to show this “circulation;” but there are many plants of which it is but necessary to take a fragment and lay it upon a slide. The _Anacharis alsinastrum_ is one of these: it grows in water, having three leaves round the stem, then a bare portion, again another three leaves, and so on. One of these leaves must be plucked close to the stem, and laid upon a slide with a drop of water. Thin glass should be placed upon it, and along the mid-rib of the leaves the “circulation” may be seen most beautifully when a good specimen has been chosen; but it requires rather more power than the Vallisneria. This plant is very common in many parts of the country, a great number of our ponds and streams being literally choked up by it. In the _Chara vulgaris_ and two or three of the Nitellæ, &c., this phenomenon may also be seen with no preparation except plucking a part from the stem and laying it upon a slide as with the Anacharis. In using the Frog-bit, the outer part of the young leaf-buds must be taken to obtain the best specimens for this purpose; but a section of the stem will also show the “circulation,” though not so well. The plants before mentioned are all aquatic, but the same movement of the globules has been observed in several kinds of land plants, as in the hairs upon the leaf-stalks of the common groundsel; but these do not show it so well, nor are they so easily managed as the above. Many microscopists who are not fortunate enough to be in the neighbourhood of these plants (indeed the Vallisneria is a foreign one) grow them in jars, so a few remarks as to the treatment they require will not be out of place. The Vallisneria requires a temperature 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 flourishes 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.