M 11.1-M 12.1 MOUNTING MEDIA 633 



11.1 Semmens 1938a CS13 — auct. Microscope, 2:120 



formula: water 40, gum arabic 20, DS 11.23 Belling 1921 



11.1 Semmens 1938b CSlS—and. Microficope, 2 -.120 



formula: water 45, gum arabic 10, chloral hydrate 25, acetic acid 37.5, carmine 0.5 

 preparation: Dissolve the chloral hydrate in 25 acetic acid with 25 water, raise to 



boiling, stir in carmine, cool, and filter. Dissolve the gum in 20 water and 12.5 acetic 



acid. Mix the solution.s. 



11.1 Swan 1936 4184, 27 :38<) 



formitla: water 20, gum arabic 15, chloral hydrate GO, glucose syrup 10, acetic acid 5 



11.1 Womersley 1943 21054, 67:181 



formula: water 100, 95% ale. 50, gum araliic (powder) 40, phenol 50, chloral hydrate 



50, glucose syrup 10, lactic acid 20 

 preparation: Mix ale. and powdered gum to a smooth paste. Flood 100 water onto 



paste. Stir rapidity. Leave 2 hours, then filter. Evaporate till volume 100. Grind phenol 



and chloral hydrate in a mortar till solution complete. Add to solution. Add syrup 



and lactic acid to mixture. 



11.1 Zirkle 1940 20540b, 16:144 



formula: water 65, formic acid 41, gum arabic 10, sorbitol 10, ferric nitrate 0.5, carmine 



0.5 

 preparation: Dissolve the gum in the solvents. Incorporate the iron and then the dye. 

 note: See also M 12.1, M 13.1 Zirkle 1940. 



12 GELATIN MEDIA 



It is presumed, in all the formulas that follow, that a gelatin is employed which will 

 give a crystal-clear solution in water. Such purified gelatins are today available on the 

 market for bacteriological use. If commercial gelatin is being used, it is necessary that 

 it should first be clarified, and directions for doing this are given in all the older for- 

 mulas. Soak the gelatin overnight, drain it carefulh', and then melt it on a water bath 

 at about 40°C. Then add, for each 100 milliliters of the fluid so produced, the wdiites of 

 tw'o fresh eggs. These are mixed thoroughlj^ with the molten gelatin and the temperature 

 of the water bath is then raised to boiling and left until the whole of the egg white is 

 coagulated. The medium must not be stirred during this time. The egg white coagulates 

 in large lumps, which may readily be strained out through cheesecloth, and which retain, 

 attached to them, all the fine particles which cause cloudiness of the gelatin. 



12.1 Formulas 



12.1 Baker 1944 Baker 1944, 173 



formula: water 65, gelatin 5, glycerol 35, cresol 0.25 



preparation : Soak gelatin in 25 water for 1 hour, then melt at 60°C. Mix glycerol in 40 

 water with cresol, then heat to 60°C. and mix with gelatin. 



12.1 Beale 1880 Beale 1880, 07 



formula: clarified gelatin 50, glycerol 50 



12.1 Brandt 1880 23632,2:69 



formula: gelatin 40, glycerol 60, phenol 0.5 



PREPARATION : Soak gelatin in water for 24 hours. Drain and melt. Mix glycerol and phenol 

 with molten gelatin. Clarify s.a. 



12.1 Bruere and Kaufmann 1907 4349, 2:11 



formula: gelatin about 25, glycerol about 50, water q.s., 40% formaldehyde 0.1 

 preparation: Soak the gelatin overnight. Drain, melt, and add an equal volume of 

 glycerol. Clarify s.a., filter, and add formaldehyde. 



12.1 Carleton and Leach 1938 Carleton and Leach 1938, 115 



formula: water 60, gelatin 10, glycerol 70, phenol 0.25 

 preparation: Melt gelatin in water at 80°C. Raise glycerol and phenol to 80°C. and add. 



