The instrument we select will depend on the use to which we intend to put it and on the length of our purse. Perhaps the question of cost will be more important to most people. An elaborate instrument is not a desirable acquisition, till we are somewhat advanced in our work at anyrate, and one of the models which most makers call Students’ Microscopes will do everything we desire. We should have at least two objectives, three if we can afford them, a 1 inch and a 1/6 inch will enable us to examine everything described in these pages, except some of the bacteria. If we wish to add a third objective we might select a 2 inch one, for quite low-power work and later we shall probably become the proud possessors of a 1/12 inch objective, but this would be of little use to us at first. Two eyepieces will complete our optical equipment. A condenser for the stage, properly known as a substage condenser is an addition which we shall appreciate, though quite interesting work may be done without it. Our other apparatus is inexpensive and comprises, one or two dissecting knives, some needles mounted in handles, a pair of fine scissors, a pair of small forceps, a razor, one or two camel hair brushes, three or four watch glasses, slides and cover slips, and a pipette or two. A pipette, by the way, is merely a glass tube pointed at one end and cut off square at the other; at about its centre it is much wider than at the top or bottom. It is a most useful piece of apparatus for picking up small water animals which we wish to examine. By putting the pointed end of the pipette just over an _Amœba_, for example, and sucking gently at the other end, we shall draw some water and the animal into the swollen part of the tube. If we then place one finger over the end of the pipette to which we have applied suction we can transfer the contents wherever we wish without it running out, as soon as we remove our finger the pipette empties itself. The dissecting knives are useful for cutting up specimens before examination, the mounted needles for teasing them, that is to say tearing them into fine shreds. The brushes we may use instead of the pipette, for picking up small objects from water, or when dry. The watch glasses are useful for examining objects such as sponges, water fleas, etc., under water. They are just as satisfactory for most purposes as the specially constructed zoophyte troughs and, of course, very much cheaper. The razor is required for section cutting concerning which we will say a few words.