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[Vol. 8 
agar. In 3 strains of A. effusus, fruiting was increased and the conidial 
areas and the reverse were citrine in color. The two strains of A. oryzae 
were more brownish in color and the conidiophores were short as compared 
with the growth of the same strains on the standard Czapek solution agar. 
A. terricola var. Americana grew sparsely on this medium. 
Fish agar {halibut): Nine strains of A. flavus when grown on fish agar 
for two months developed only a few brown heads; nine other strains of 
the same species developed only white mycelium. A. oryzae dind A. effusus 
also did not fruit. A. tamari and A. Wentii, however, showed fruiting at 
first old gold in color and scarcely spreading beyond the mark of the streak. 
Beef plugs: Plugs of fresh beef were cut with a cork borer and placed in 
tubes ordinarily used for potato plugs. The sterilization was fractional. 
At the end of two weeks six of the more common strains which develop 
conidial areas near in color to Kronherg's green on Czapek solution agar 
were olive ocher (Ridgway XXX. 21") on the beef, four others ran through 
olive ocher to old gold (Ridgway XVI. 19' i) ; three strains changed from 
olive ocher to other tints and shades of orange and yellow; one strain never 
developed any deeper color than deep colonial buff (Ridgway, XXX. 21" h). 
All the green color was, therefore, eliminated from these strains of A. flavus 
when grown on cooked beef, with the exception of one strain which became 
lime green after it had appeared olive ocher. The early growth of A. para- 
siticus was at first mignonette green and later olive lake (Ridgway XVI. 2' i), 
a shade with no green; a yellow green strain (no. 129), possibly A. micro- 
virido-citrinus , corresponding with A. terricola of the brown series, was 
colonial buff (Ridgway XXX. 21") \ and strains of A. effusus at the end of 
two weeks were chamois (Ridgway XXX. 19' b). No green color was 
exhibited in the whole group. 
Plain agar {bacteriological) : The A . flavus group when planted on plain 
agar produced color practically as when grown on beef plugs. The green 
factor was not suppressed as completely, however. It was more evident 
during the first few days of growth, and seemed to disappear except in the 
same instances noted under beef plugs. 
Synthetic agar {Currie s) :'^^ Thirteen of the A. flavus strains and A. 
parasiticus developed the green color more intensely with a reduction of 
yellow, when grown on this agar. They developed such shades and tints 
as Kildare green (Ridgway XXI. 29" b), Rainette's green (Ridgway XXI. 
27" i), cress green (Ridgway XXI, 29'' k), etc. Six similar strains grew as if 
on Czapek solution agar, as did also A. effusus. 
In these experiments the colors reported range from mixtures of yellow 
and orange to various combinations of yellow and green. The reversible 
factor appears to be green. Kita^^ reports similar observations. In 
^ (NH4)H2P04, 2.0 gms.; KCl, 0.2 gm.; MgS04, o.i gm.; cane sugar, 30 gms. ; 
agar, 15 gms.; H2O, i 1. Formula used by Dr. J. N. Currie, 
^1 Kita, Gen-itsu. Ueber die Konidienbildungsfaehigkeit einiger Varietaten des 
Aspergillus Oryzae. Original Communications, 8th International Congress of Applied 
Chemistry 14: 95. 
