LABORATORY EQUIPMENT AND METHODS 453 



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 1 5 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 w r ill 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 Roll, 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 Uni- 

 versity, California. Ward's Natural Science Establish- 

 ment, 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 prepara- 

 tions 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 



