DEPARTMENT OF AGRICULTURE 
Vol. VII Washington, D. C., October 2, 1916 No. 1 
ASPERGILLUS NIGER GROUP 
By Charles Thom, Mycologist , Bureau of Chemistry , and James N. Currie, Dairy 
Chemist , Bureau of Animal Industry 
OXALIC-ACID PRODUCTION OF SPECIES OF ASPERGILLUS 
The recent discovery by the writers of an oxalic-acid-forming species of 
Penicillium 1 led from a review of the subject of oxalic-acid production 
by molds to a study of the black forms of Aspergillus spp. Wehmer, in 
1891, 2 showed that A.niger is a very active oxalic-acid-producing fungus. 
The question whether this ability to produce oxalic acid is possessed in 
equal degree by all strains of A. niger has not been heretofore discussed. 
Culture hi, received from Amsterdam, Netherlands, 3 as A . niger , was 
selected for comparison with Penicillium oxalicum , because this strain 
was supposedly obtained originally from Wehmer. 
Aspergillus niger has been the subject of a large number of biochemical 
researches. Back of this selection lies its apparent ease of specific 
identification, together with, as a corollary, the assumption that the study 
may be repeated elsewhere by isolating a black species of Aspergillus. 
Antithetic to this point of view there occurs in the literature a series of 
specific names and descriptions of black or dark-brown species, most of 
which rest upon minor. morphological characters plus the assumption 
that occurrence upon hosts or substrata of widely different nature is evi¬ 
dence of specific difference. 
Wehmer, in 1901, 4 cited 18 such names; at least 25 may now be found 
in the literature. Comparative culture may ultimately show how many of 
these may be separated by characters definite enough to be used in 
descriptive work. 
The possible bearing of the comparative study of oxalic-acid pro* 
duction upon the problem of relationship among this lot of strains or 
1 Currie, J. N., and Thom, Charles. An oxalic add producing Penidllium, In Jour. Biol. Chem., v. 22, 
no. 2, p. 287-293, 1 fig. 1915. 
2 Wehmer, Carl. Entstehung und physiologische Bedeutung der Oxalsaure in Stoffwechsel einiger 
Pilze. In Bot. Ztg., Jahrg. 49, p. 233ft. 1891. 
8 By courtesy of Dr. Johanna Westerdijk. 
* Wehmer, Carl. Die Pilzgattung Aspergillus in morphologischer, physiologischer und s ystematischer 
Beziehung unter besonderer Berucksichtigung der mitteleuropaeischen spedes. V. Systernatik. C. 
Schwarzbraune Arten. In Mem. Soc. Phys. et Hist. Nat. Gen&ve, t, 33, pt. 2, no. 4, p. 103-m. 1901. 
Vol. VII, No. r 
Oct. 2, 1916 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
