8 
Journal of Agricultural Research 
Vol. VII, No. i 
others from 3 to 4/x, a few from*3 to 4.5/i, and in A. carbonarius from 6 to 
10/x. Conidial walls are typically rough, with irregular, but usually 
oblong or barlike masses of coloring matter [the aspergillin of Linos- 
sier 1 ] which run lengthwise of the conidial chain, and are absent at the 
ends of the spore or are replaced there by the connective when such is 
present. In some forms these bars are more or less completely broken 
up to form irregularly disposed rough tubercles. In experiments this 
coloring substance was dissolved by soaking in hot water, after which 
the original outer cell wall became visible. This experiment indicates 
that the difference in color between strains is due to the varying amount 
of aspergillin deposited between the outer, or primary, and inner, or 
true, spore walls. Upon careful study, A. fuscus (one of SchiemamTs 2 
mutants from A. niger) showed delicate traces of the typical bars of 
color; A. cinnamomeus with its much lighter color and smooth spores 
showed only diffused, not localized color. 
Details in colonies of the same strain differ in successive cultures. 
These differences are nearly all quantitative, but they indicate great 
power of response to the stimulation of environment. The mutants, 
A. cinnamomeus and A. fuscus , separated by Schiemann, 2 differ from 
the usual form only in intensity of color, yet maintain these characters 
consistently in culture. A. carbonarius (4030.1) is a gigantic form in 
which the proportions are approximately quadrupled, while No. 2580 
(A. strychni ?) shows the same measurements except that the conidia re¬ 
main with a maximum diameter of 4 to 4.5^. Perhaps A. niger is a form 
comparable to Oenothera spp. in its tendency to produce mutants. There 
arise, therefore, a few forms with characters sufficiently tangible to 
separate by description. In a majority of the strains met with in cul¬ 
ture, morphological differences are not sharp enough for diagnostic pur¬ 
poses. Nevertheless great and fairly stable differences in physiological 
activity are found among them. Two forms morphologically alike may 
thus differ greatly in economic importance. 
Nomenclature. —Current literature has accepted the name “ As - 
pergillus niger ” Van Tieghem, 3 for the black species of Aspergillus. 
Sterigmatocystis autacustica Cramer, obtained from a human ear, was 
undoubtedly one of the series of organisms, but was insufficiently 
described. A. ficuum (Reich.) P. Hennings, first named u Ustilago 
ficuum” by Reichardt in 1867, differs slightly in measurements, but the 
presumption of identity is based upon the constant occurrence of the 
1 Linossier, Georges. Sur une h^matine v£g4tale l’aspergilline. In Compt. Rend. Acad. Sci. [Paris]; 
t. 112, no. 15, p. 807-808. 1891. 
-Sur une hdmatine v^getale: raspergilline, pigment des spores de l’Aspergillus niger. In Compt. 
Rend. Acad. Sci. [Paris], t. 112, no. 9, p. 489-492. 1891. 
2 Schiemann, Elizabeth. Op. cit. 
8 Van Tieghem, P. E. L. Rec&erches pour servir k l’histoire physiologique des Mucedin^es. Fermenta¬ 
tion gallique. In Ann. Sci. Nat. Bot., s. 5, t. 8, no. 4, p. 240. 1867. 
