Suppose, for example, we desire to stain a section in Carmalum, a mixture of Carminic Acid 1 grain, Alum 10 grains, hot distilled water 200 c.c. We take three watch glasses, in one we place a few drops of our stain, in another water, and in the third alcohol. Our section is placed in the watch glass containing the carmalum and is left there for about two minutes, then with the help of a small brush it is transferred for a similar period to the watch glass containing water, and finally it is placed in the alcohol. From the last watch glass it may be transferred to glycerine jelly on a slide and mounted as already described; Carmalum stains our section a beautiful pink. There is a temptation to buy a large stock of stains of all hues and of varied composition. The temptation should not be allowed to get the better of us. In our early days at anyrate, we shall do far better if we use but few stains and learn to understand their peculiarities. The most useful selection for the beginner will comprise Haematoxylin, Safranin, Eosin, Carbol-Fuchsin, Methylene Blue, and Carmalum. These should all be obtained ready for use: this will save errors in compounding, and, in certain cases, will save time; some of the stains, Haematoxylin for example, are not fit for use till months after they have been mixed with the other ingredients which form the complete stain. Frequently when examining small but lively water animals we may feel the necessity of some method of sobering them. All the little organisms, both plants and animals, which are provided with the little whip-like structures mentioned so often in our pages, are difficult to examine whilst they are in motion. There are many substances, we might add, which would kill them, but in doing so we shall nearly always find that they contract to such an extent as to lose all semblance of their natural shape, and become useless as objects for our microscope. Should our inclinations lead us in the direction of much study of these little beings, we shall do well to keep handy a small bottle of Rousselet’s solution; it is composed of 2 per cent. solution of hydrochlorate of cocaine, 3 parts; Methylated Spirit, 1 part; water, 6 parts. Any chemist will mix the solution for us. When we have occasion to examine a too lively specimen, we simply run a drop of the solution under the cover slip, as described in our remarks on staining with iodine, and the creature we are examining will abandon its frolics and conveniently remain in a fully expanded state.