1 84 



Tannic Acid Fermentation 



be grouped with the genus Citromyces as founded by Wehmer; but Thorn" 

 does not consider this a valid basis for differentiation of genera, and 

 prefers to include this form of conidiophore under the genus Pemeillium. 

 This latter concept is here followed. 



Description of organism. Colonies on 15 per cent gelatin are, when young, 

 of a faint green color which changes to an otter brown. On 15 per cent gela- 

 tin + 3 per cent sugar the olive green changes to ashy gray and then to 

 greenish black. On bean agar the color is at first bluish green, and changes 

 to dark olive green, and finally to a grayish color. The surface is velvety. 

 The conidiophores arise vertically from the substratum and in length vary 

 from 100/i to 700^. The fructification averages 90m in length (it may be 200^), 

 and its width is approximately 15m. The conidiiferous cells average 10m 

 in length, the conidia are spherical, and 3m in diameter. A single whorl of 

 simple conidia-bearing cells only is present as is represented by figures 1 

 and 2. 



Fig 1. Fig 2. 



Conidial fructification showing simple conidiferous cells (X 600). 



Cultural character. At room temperature 15 per cent gelatin is liquified 

 in six days with the production of a strong ammoniacal odor; in the pres- 

 ence of 3 per cent sugar the total liquefaction is retarded a day or more. 

 The presence of b§an juice still longer delays the liquefaction of the gelatin. 

 On 15 per cent gelatin + 3 per cent sugar, the lower surface is colored yellow- 

 ish to reddish brown, when grown in solution B -|- 10 per cent cane sugar the 

 lower surface of the mycelial felt may be of a salmon color. Fruiting on such 

 a solution at room temperature usually requires eight days. This organism 

 possesses the ability to ferment tannic acid and with 10 per cent tannic 

 acid in solution B at a temperature of 30°C., gallic acid may be precipitated in 

 about seven days. 



Gall nut Penicillium. Only one other species of Penicillium has so far 

 been found to grow on 10 per cent tannic acid, and this is the one isolated 

 from the gall nuts. It grows more slowly in 10 per cent tannic acid. In the 

 presence of sugar it produces an intensely red color in the substratum and is 

 a slow liquefier of gelatin. It differs from the other also in possessing more 

 than one whorl of conidiiferous cells, and has other distinguishing features. 

 It appears to be Penicillium rugulosum. 



*^ hoc. cil. 



