100 Methods in Plant Histology 



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 turpentine 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 per cent 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 immediate mounting, may be put into small vials or shells, where 

 it can be kept indefinitely. The shells should be kept out of the light. 



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 per cent glycerin and allow the glycerin to con- 

 centrate. 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 95 per cent 

 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 per cent solution in 90 per cent alcohol. We use the stain 

 much stronger than recommended by Pfeiffer and Wellheim. This 

 solution, diluted with an equal volume of 95 per cent alcohol and 

 allowed to act for 24 hours, does not stain too deeply. 



2. Rinse the material for a minute in 90 per cent alcohol. 



3. Stain in anilin blue, using a 1 per cent solution in 90 per cent 

 alcohol, diluted with four times its volume of 90 per cent alcohol. We 

 prefer to make a fresh solution every time we have anything to stain. 

 It is not necessary to measure it. A little of the powder about 



