238 SUMMARY OF GUKRENT KESEARCIIES RELATING TO 



an exsiccator as follows : place a saucer full of soda lime (sodium 

 hydroxide with lime) on a plate of glass, and cover with a bell- jar. 

 This is a simple and effective exsiccator. Instead, you may simply 

 scatter soda lime in the bottom of any low museum jar with tight- 

 fitting cover. The saucer of soda lime may be placed on a smooth 

 board and covered with a perfectly tight box. You may improvise other 

 forms ; the essential thing is to provide a small air-tight space in which 

 the soda lime may work. Instead of soda lime you may use fused 

 calcium chloride or the white sticks of sodium hydroxide. Paint the 

 exsiccator black, or cover it with black paper, or in some other way shut 

 out the light. Many stains are weakened by light. 



We are now ready for the transfer from absolute alcohol to the 10 p.c. 

 Venetian turpentine. 3Iake the transfer qukldy. Pour off the absolute 

 alcohol and place the dish, with the material, in the exsiccator : then 

 pour on the 1(> p.c. turpentine, and immediately put on the cover. This 

 is better than to pour on the turpentine and then try to get the dish well 

 placed in the exsiccator. The greater the surface of soda lime exposed, 

 the more rapid will be the concentration of the Venetian turpentine. 

 The concentration must not be too rapid. Not less than two days 

 should be allowed for the concentration of 30 c.cm. of the turpentine 

 in an ordinary Minot watch-glass. Great care must be taken not to let 

 any of the soda lime, or other drier, get into the turpentine. As soon as 

 the turpentine has attained the consistency of pure glycerin, it may be 

 exposed to the air without any danger from moisture ; but the tur- 

 pentine would soon become too thick for mounting. If the turpentine 

 has become too thick, thin it with a few drops of absolute alcohol, or 

 with 10 p.c. or any thin solution of Venetian turpentine. 



Mount the material in a few drops of the Venetian turpentine, and add 

 a cover. Square covers may be used, since it is entirely unnecessary to 

 seal the mounts. Such mounts are as hard and durable as balsam mounts. 

 Material in the thickened Venetian turpentine, if not needed for imme- 

 diate mounting, may be put into small vials or shells, where, kept out of 

 the light, it can be kept indefinitely. We recommend a No. 4 shell. 

 The corks should be of the best quality, otherwise the turpentine will 

 become too thick. While it can be thinned by adding thin turpentine, 

 it is better, for easy mounting, not to let the turpentine become too 

 thick. 



Magdala Red and Anilin Blue. — Fix in chromo-acetic acid and wash 

 in water, as described in the previous schedule. Transfer from water 

 to 10 p.c. glycerin and allow the glycerin to concentrate. It is not 

 necessary to use an exsiccator, since there is no danger from moisture in 

 the air. When the glycerin attains the consistency of pure glycerin, 

 wash the glycerin out with 1)5 p.c. alcohol and then proceed with the 

 staining. (1) Stain in Magdala red. At least two Magdala reds are 

 sold by dealers. The one marked edit is more expensive, but, in our 

 experience, is inferior to the one marked simply Magdala red. Make a 

 1 p.c. solution in 90 p.c. alcohol. We use the stain much stronger than 

 recommended by Pfeiffer and Wellheim. This solution, diluted with 

 an equal volume of 95 p.c. alcohol and allowed to act for 24 hours, does 

 not stain too deeply. (2) Rinse the material for a minute in 90 p.c- 



