THE GLYCERIN METHOD 105 



select protonema showing the very young moss plants. The brown 

 protonema and bi'own bulbils preserve their color perfectly. Wash the 

 dirt away from the protonema, which is then placed in 50 per cent 

 glycerin. Let the glycerin concentrate, transfer to glycerin jelly, and 

 mount in the usual way. 



The method is very useful when one finds a single specimen of 

 Pediastrimi, or any small form which would be lost in the more com- 

 phcated processes. Place a large drop of 10 per cent glycerin on a 

 shde; with a pipette, transfer the object to the drop, and allow the 

 glycerin to concentrate. Then add a cover and seal the mount. 



GLYCERIN JELLY 



It is almost never necessary to mount anything in glycerin, because 

 material can be transferred directly from glycerin to glycerin jelly. 

 If the glycerin jelly is well made, it is quite firm and mounts will last 

 for a year or two, without sealing; but it is better to seal them with 

 balsam. A very good formula is known as Kaiser's gelatin. It is made 

 as follows: One part by weight of the finest French gelatin is left for 

 about 2 hours in 6 parts by weight of water; 7 parts of glycerin are 

 added, and for every 100 grams of the mixture, 1 gram of concentrated 

 carbolic acid. The whole is warmed for 15 minutes, stirring all the 

 while until all the flakes produced by the carbolic acid have disap- 

 peared. Filter while warm through a fine-mesh cheesecloth. 



To make a mount, take a small piece of the glycerin jelly, not more 

 than half as large as a grain of wheat — the exact size will depend upon 

 the material — warm it until it melts, and then transfer to it the mate- 

 rial which has already been brought into thick glycerin. It is a good 

 plan to touch the material to filter paper in order to remove as much 

 glycerin as possible; for the less glycerin the firmer the mount will be. 

 The mount may be sealed as soon as it is cool; but some prefer to let it 

 stand for a week or two before sealing. In any case, it is a fairly firm 

 mount, so that there is no danger of moving the cover. 



Everything which can be brought safely into pure glycerin can be 

 mounted in glycerin jelly, and the preparation is much more stable 

 than a glycerin mount. 



