592 LABORATORY EXERCISES 



in a well-stoppered bottle, because of the volatility of the alcohol. If it becomes too 

 concentrated by evaporation, and thus stains too deeply, or forms a precipitate on 

 the blood smear, the addition of a suitable quantity of methylic alcohol will correct 

 quickly such fault. It does not undergo any other spontaneous change e.xcept that 

 of concentration by evapoiation. 



Differential Staining tf Fitngcits and Host Cells. — Another useful method is set 

 forth in the following: 



Vaughan, R. E. : A Method for the Differential Staining of Fungous and Host 

 Cells. Ann. Mo. Bot. Gard., i: 241, 242. 



LESSON 4 



Liquid Nulrienl Solutions. — Synthetic culture media (see Smith: Bacteria in 

 Relation to Plant Diseases, i: 197): 

 Tasteitr's Culture Fluid (Yeasts) : 



Ammonium tartrate 10 gr. 



Ashes of yeast 10 



Rock candy 100 



Distilled water 1000 c.c. 



Dissolve cold. 



Naegeli's Nutrient Solution. 



Calcium chloride o. i gr. 



Magnesium sulphate 0.2 



Dipotassium phosphate i .0 



Ammonium tartrate 10. o 



Distilled water 1000. o c.c. 



Cohn's Nutrient Solution. 



Distilled water 1000. o c.c. 



Acid potassium phosphate 5 . o gr. 



Magnesium sulphate 50 



Neutral ammonium tartrate 10.0 



Potassium chloride 0.5 



(DeBary, p. 86, Vorles. liber Bakterien, 2 Auflage). 



Raulin's Culture Fluid. 



Magnesium carbonate. . 0.40 gr. 



Ammonium sulphate. . . o. 25 



Zinc sulphate 0.07 



Ferrous sulphate o. 07 



Potassium silicate 0.07 



