_Preparing skeletons._--In general, skeletons are best cleaned by boiling. After most of the flesh has been cut away the skeleton should be boiled in a soap solution until the remaining parts of the muscles are thoroughly softened. The soap solution is made of 2,000 c.c. of water, preferably distilled, 12 grams of saltpetre, and 75 grams of hard soap (white). Heat these until dissolved, then add 150 c.c. of strong ammonia. This stock solution is mixed with four or five parts of water, when the mixture is ready for use. The bones after boiling are rinsed in cold water, brushed and picked clean, then left to dry on a clean surface. _Preserving anatomical preparations._--Many specimens worth keeping will be found, and for them a solution known as Fischer's formula is suggested as good, especially for brains. Fischer's formula is made up as follows: 2,000 c.c. of water, 50 c.c. of formalin, 100 grams of sodium chloride, and 15 grams of zinc chloride. These are mixed together until thoroughly dissolved. Open preparations well before placing them in the liquid and use about twenty times the volume of the object to be preserved. _To keep fresh dissections._--For materials which are dissected fresh and must be kept over for several days in a fresh condition add a few drops of carbolic acid to the water which covers them. Carbolized water (2 per cent in water) will preserve a great many tissues for a long time. Hearts will remain for years in a supple condition in this solution. _Obtaining marine animals, microscopic preparations, etc._--For schools not on the seashore the marine animals such as starfishes, etc., which are to be dissected or examined as examples of the branches to which they belong must be obtained as preserved specimens from dealers in such supplies. Among such dealers on the Atlantic coast are the Marine Biological Laboratory, Woods Holl, Mass.; F. W. Walmsley, Academy of Natural Sciences, Philadelphia, Pa.; and H. H. and C. S. Brimley, Raleigh, N. C.; on the Pacific coast the Supply Department, Hopkins Seaside Laboratory, Stanford University, California. Ward's Natural Science Establishment, Rochester, N. Y., supplies almost any biological specimens asked for. This establishment furnishes already made dissections and sets illustrating life-history and metamorphosis. The few permanent microscopic preparations which are mentioned in the book as desirable to have can be made by the teacher if he has had any training in microscopical technic. If not, they may be bought cheaply of such dealers in natural history supplies as the Bausch & Lomb Optical Co., Rochester, N. Y.; the Kny-Scheerer Co., 17 Park Place, New York City; Queen & Co., 1010 Chestnut Street, Philadelphia, Pa., and numerous others. From these dealers also can be bought all of the laboratory supplies, such as lenses, slides, cover-glasses, dissecting-scalpels, scissors and needles, etc., mentioned in this book.