Aspergillus Niger, Van Tieghem. 



Origin. — In putrid substances; in the lungs of birds. 



Color. — Black or dark brown. 



Mycelium. — This is low and, -at first white, then brown- 

 ish or black. 



Fruit-organs. — The fruit hyphas are spherical, or flask-, 

 or club-shaped at the end, and this enlargement is covered 

 with radially arranged, minute bottle-shaped bodies — the 

 intermediate spore bearers or sterigmce — from which rows of 

 spores extend. The sterigmae are divided. The spores 

 are black or brownish and spherical, and are 3-5 ^ in 

 diameter. 



Growth. — Slow. 



Bread fiasks. — It forms a low growth whicli becomes very black. 



Temperature. — The optimum is about 35°. 



Pathogenesis. — Intravenous injection of spores in rab- 

 bits is not followed by as malignant results as with the 

 next two forms. It gives rise to diastatic, inverting and 

 other ferments. 



Aspergillus Flavescens, Wreden. 



Origin. — White bread. ' 



Color. — ^At first whitish, eventually pale yellow or yel- 

 lowish green. 



Mycelium. — The mycelial threads and spores are' 

 smaller than those of A. niger. 



Fruit-organs. — The club-shaped ends of the fruit 

 hyphae are covered with sterigmae, from which extend 

 rows of spores, as in A. niger. The spores are yellowish 

 or brownish in color and are 5-7 /« in diameter. 



Growth. — Rapid. 



Bread Aasks. — Grows best on bread where it forms a yellowish, 

 low growth. 



Temperature. — The optimum is about 28°, but it grows 

 well in the incubator. 



Pathogenesis.— It is more pathogenic than A. niger, 

 and less than A. fumigatus. 



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