NAEGELI'S SOLUTION IQI 



3. Weigh out sheet gelatine, 70 grammes, cut it into small 

 pieces and add it to the contents of the flask. 



4. Bubble live steam through the mixture to dissolve the gela- 

 tine and agar. 



5. Weigh the flask and contents. Adjust the weight to the 

 calculated figure for one litre of medium (1110.5 grammes) by the 

 addition of distilled water at 100 C. (vide page 166). 



6. Cool to below 60 C. and clarify with egg. 



7. Filter through papier Chardin. 



8. Tube, and sterilise as for nutrient gelatine. 



Shake well after the final sterilisation, to aerate the medium. 



Media for the Study of Yeasts and Moulds. 

 Pasteur's Solution. 



(Reaction alkaline). 



1. Weigh out and mix the ash from 10 grammes of yeast; 

 ammonium tartrate, 10 grammes; cane sugar, 100 grammes. 



2. Dissolve the mixture in distilled water, 1000 c.c. 



3. Tube or flask, and sterilise as for nutrient bouillon. 



Yeast Water (Pasteur). 



1. Weigh out pressed yeast, 75 grammes; place in a 2 -litre flask 

 and add 1000 c.c. distilled water. 



2. Heat in the steamer at 100 C. for thirty minutes. 



3. Filter through papier Chardin. 



4. Tube or flask, and sterilise as for nutrient bouillon. 



Cohn's Solution. 



1. Weigh out and mix 



Acid potassium phosphate (KH 2 PO 4 ) .5.0 grammes 



Calcium phosphate 0.5 gramme 



Magnesium sulphate 5.0 grammes 



Ammonium tartrate 10.0 grammes 



and dissolve in 



Distilled water 1000 c.c. 



2. Tube, or flask and sterilise as for nutrient bouillon. 

 Naegeli's Solution. 



1. Weigh out and mix 



Dibasic potassium phosphate (K 2 HPO 4 ) i.o gramme 



Magnesium sulphate o . 2 gramme 



Calcium chloride o . i gramme 



Ammonium tartrate 10.0 grammes 



and dissolve in 



Distilled water . . . . - 1000 c.c. 



2. Tube or flask; sterilise as for nutrient bouillon. 



