Mounting Media {mountants) 119 



index, and (3) glycerols and glycol as plasticizing agents. Gum arabic 

 slowly hardens by drying, gelatine sets by cooling, and the glycerol keeps 

 them from cracking or overlrying. The addition of phenol, thymol, 

 merthiolate, or Zephiran prevents mold growth. 



Kaiser's Glycerol Jelly 



water 52.0 ml. 



gelatine 8.0 gm. 



glycerol 50.0 ml. 



Preserve with either (I) carbolic acid (phenol), 

 O.I gm.; (2) merthiolate, 0.01 gm.: or (3) 

 Zephiran 0.1 ml. 



Allow gelatine to soak for 1-2 hotirs in water, add glycerol and pre- 

 servative. Warm for 10-15 minutes (not over 75°C) and stir until 

 mixture is homogeneous. This keeps well in covered jar in refrigera- 

 tor. If heated above 75 °C, the gelatine may be transformed into meta- 

 gelatine and will not harden at room temperature. 



Apathy's Gum Syrup 



gum arabic (acacia) 50.0 gm. 



sucrose (cane sugar) 50.0 gm. 



distilled water 50.0 ml. 



formalin 1.0 ml. 



Dissolve lumps of gum arabic in warm ^vater; add sticrose. \V^hen 

 dissolved, filter and allow to cool. Add formalin. Do not use powdered 

 form of gum; it makes a milky solution, Avhereas the lump form pro- 

 duces a clearer medium. The cover glass does not have to be sealed as 

 it does with Kaiser's glycerol jelly above. 



Farrant's Medium 



distilled water 40.0 ml. 



gum arabic (acacia) 40.0 gm. 



glycerol 20.0 ml. 



carbolic acid (phenol) 0.1 gm. 



(or merthiolate or Zephiran) 



It is difficult to obtain a good quality of gum arabic to make a clean 

 and clear solution, so purchasing of the finished product from Amend 

 Drug and Chemical Company is preferable. 



