becomes detached from the thread, assumes an oval shape and sinks to the bottom of the pond, where it rests awhile. At a later period the cell wall bursts and a new thread of _Spirogyra_ develops from it. When we are examining _Spirogyra_ we may notice some very minute brick-red, spherical bodies adhering to the green threads. These are little pond animals, known by the name of _Vampyrella Spirogyræ_. This little creature passes through an interesting and easily observed series of changes. Its life is very uneventful, consisting of a good meal of _Spirogyra_, a period of rest followed by an increase, and this is repeated over and over again. If we watch our little sphere through the microscope, we may be lucky enough to see the contents divide into four parts. Now we must watch carefully, for very interesting events are about to take place. Each of the four parts into which the contents of the sphere has split, escapes into the water and swims about for a time; it then becomes spherical, but instead of having a smooth outer surface, as it had when we first observed it, we can see that it is now studded all over with very fine threads. It then wanders along a _Spirogyra_ plant, attaches itself to one of the cells, perforates its wall and sucks out the contents. This performance it repeats several times then, evidently satiated, it loses its threads and resumes the appearance it had when first observed and thus it rests, till division of its contents into four parts takes place once more and the little comedy is repeated. Now we must tear ourselves away from our pond; there are very many interesting objects for our microscope on the sea shore and if we delay too long here, we shall not be able to give them the attention they deserve. CHAPTER VII THE MICROSCOPE AND PLANT LIFE The science of botany consists of many branches and, in most of them, the microscope is the scientist’s constant aid. The study of bacteria, really a branch of botany, we have dealt with in another chapter, so here we will omit these interesting though lowly plants. By far the number of botanical objects for the microscope consist of sections--exceedingly thin slices of whatever portion of the plant is being examined, cut either with a sharp razor or a special instrument called a microtome. Section cutting, though not a difficult accomplishment, requires a considerable amount of practice and cannot be learned from a book; all our descriptions, therefore, will be confined to objects from the plant world which may be studied without the assistance of razor or microtome.