Let it be understood, that in giving the description of those articles which are usually esteemed _necessary_ in the various parts of microscopic manipulation, I do not mean to say that without many of these no work of any value can be done. There are, as all will allow, certain forms of apparatus which aid the operator considerably; but the cost may be too great for him. A little thought, however, will frequently overcome this difficulty, by enabling him to make, or get made, for himself, at a comparatively light expense, something which will accomplish all he desires. As an example of this, a friend of mine made what he terms his “universal stand,” to carry various condensers, &c., &c., in the following way:--Take a steel or brass wire, three-sixteenths or one-quarter inch thick and six or eight inches long; “tap” into a _solid_, or make rough and fasten with melted lead into a _hollow_, ball. (The foot of a cabinet or work-box answers the purpose very well.) In the centre of a round piece of tough board, three inches in diameter, make a hemispherical cavity to fit half of the ball, and bore a hole through from the middle of this cavity, to allow the wire to pass. Take another piece of board, about four inches in diameter, either round or square, and one-and-a-half or two inches thick, make a similar cavity in its centre to receive the other half of the ball, but only so deep as to allow the ball to fit tightly when the two pieces of board are screwed together, which last operation must be done with three or four screws. Let the hole for the wire in the upper part be made conical (base upwards), and so large as only to prevent the ball from escaping from its socket, in order that the shaft may move about as freely as possible. Turn a cavity, or make holes, in the bottom of the under piece, and fill with lead to give weight and steadiness. This, painted green bronze and varnished, looks neat; and by having pieces of gutta-percha tubing to fit the shaft, a great variety of apparatus may be attached to it. Again, a “condenser” is often required for the illumination of opaque objects. My ingenious friend uses an “engraver’s bottle” (price 6d.), fills it with water, and suspends it betwixt the light and the object. Where the light is very yellow, he tints the water with indigo, and so removes the objectionable colour. I merely mention these as examples of what may be done by a little thoughtful contrivance, and to remove the idea that nothing is of much value save that which is the work of professional workmen, and consequently expensive. CHAPTER II. TO PREPARE AND MOUNT OBJECTS “DRY.” The term “dry” is used when the object to be mounted is not immersed in any liquid or medium, but preserved in its natural state, unless it requires cleaning and drying.