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CULTUBAL STUDIES OF SPECIES OF PENICILL1UM. 



CULTURAL DATA. 



Color light blue-green, olive, or gray in various media; reverse, white or cream; 

 color in media, none or slightly yellowish. 



Odor, none. 



Fifteen per cent gelatin in water, small olive-green colonies; liquefaction, rapid — 

 6 to 7 days; litmus reaction, alkaline. Potato agar and bean agar, typical. Potato 

 plugs, typical. Raulin's fluid, typical. Cohn's solution, slow and weak-growing 

 colony. 



Synthetic fluid (Dox's), carbon supplied as: Cane sugar, good growth even up 

 to 60 per cent, acid reaction. Lactose, 3 per cent, slow abnormal growth. Lactic 

 acid, 0.9 per cent, small but characteristic colony. Levulose, 3 per cent, small colo- 



Fig. 2Z.—Penicillium No. 37: a, typical branched fructification, two verticils of conidiiferous cells (XI, 600); 

 6, c, conidiiferous cell and conidia (X 1,600); d, e, sketches of conidial fructifications from potato-agar 

 culture (X 140); /, g, sketches from an old culture on 3 per cent cane-sugar agar, showing simple (g) and 

 branched (/) forms (X 140); h, j, fc, branching of conidiophore, swollen ends of branches (X 1,600); I, m, 

 germination of conidia (X 1,600). 



nies. Galactose, 3 per cent, typical. Glycerin, 3 per cent, small growth. Potato 

 starch, typical. Butterfat, slow growth, deep heavy green colony. 



Milk, curdling (0.25 per cent calcium chlorid added), rapid; digestion rapid and 

 complete; color, none. 



At 37° C, killed; check at 20° C, grew well. 



PENICILLIUM No. 12. 



This form differs from P. citrinum in producing no coloration of the medium and 

 in producing conidial fructifications in which the chains of conidia are more or less 

 divergent instead of aggregated into columns. In culture there is general corre- 



ct The time of curdling is almost impossible to determine in cases where digestion 

 begins quickly and progresses rapidly. 



