378 BULLETIN No. 189 [June, 



APPENDIX 



COMPOSITION OF MEDIA USED IN EXPERIMENTS 



Corn-Meal A gar (Shear*). To 4 teaspoonfuls of corn meal add 1 liter of dis- 

 tilled water. Keep in water bath for one hour at a temperature below 60 C. 

 Strain thru gauze, and to the filtrate add J percent agar flour. Steam three-quarters 

 of an hour. Filter thru paper tube and place in autoclave for 15 minutes at 

 115 C. 



Green-Bean Agar. 300 grams young string beans cooked in 500 ce wator 

 for one hour and strained thru cloth. 15 grams agar (powdered) melted in 500 cc. 

 water. Mix the two, add enough water to make 1000 cc., add 6 to 8 grams egg 

 albumen, and boil in autoclave. Filter thru cotton. 



Oat Agar (Clinton*). 200 grams oats ground fine thru a coffee mill and 

 soaked in 500 cc. water for one hour. 15 grams agar melted in 500 cc. water and 

 strained thru cheesecloth. Mix the two but do not filter, since the most nutrient 

 part of the medium would be lost. 



Potato Agar. 300 grams peeled potatoes, sliced as thin as possible and cooked 

 in 500 cc. water for one hour. Strain thru cloth. 15 grams agar (powdered) 

 melted in 500 cc. water. Mix the two and add enough water to make 3000 cc. 

 Add 6 to 8 grams egg albumen (powdered) and boil in autoclave for a short time. 

 Filter thru cotton. 



Potato-Glucose Agar. 290 grams peeled potatoes, sliced as thin as possible 

 and cooked in 500 cc. water for one hour. Strain thru cloth and add 20 grams of 

 glucose. 15 grams agar (powdered) melted in 500 cc. water. Mix the two, add 

 enough water to make 1000 cc., add 6 to 8 grams egg albumen (powdered), and 

 boil in autoclave for short time. Filter thru cotton. 



Agar (CooTc c ) 



Water 1000.00 cc. 



Agar 15.00 grams 



Glucose 20.00 



Ammonium nitrate 1.00 



Potassium nitrate 1.00 



Ammonium sulfate 1.00 



Magnesium sulfate .25 



Dipotassium phosphate .25 



Calcium chlorid d 01 



GROWTH ON MEDIA 

 " ALFALFA" 



On Corn-Meal Agar. Growth poor and rather slow. Mycelium white, fine, 

 submerged, and scarcely visible. No coloring of the medium. No zonation. 



On Green-Hean Agar. Growth poor and slow. Mycelium white, fine, loose, 

 and becoming somewhat tufted. Zonation. Like strain from corn. 



On Potato Agar. Growth rather slow. Characterized by the dark color 

 of the mycelium and the turning of the medium to a darker color. Hypha3 loose, 

 fine, and practically all submerged. No zonation. 



"U. S. Dept. Agr., Bur. Plant Indus., Bui. 252, 15. 1913. 

 b Conn. Sta. Rpt. (1909-10), 32, 760. 1911. 

 c Del. Sta. Bui. 91, 12. 1911. 

 d Omitted from formula used. 



