4 
Journal of Agricultural Research 
Vol. VII, No. i 
these media and grown at 37 0 . At the end of that time they were 
reexamined for oxalic-acid production. The tabulated results are given 
in Table II, with the forms arranged in the same order as in Table I. The 
quantity of N/10 sodium hydroxid required to neutralize the free acid and 
the oxalate radical is shown in separate columns. The column marked 
‘average ’ ’ represents the average of the four previous figures. 
Table; II .—Comparative oxalic-acid production of 10 strains of a black species of Asper¬ 
gillus grown at S 7 ° C ., through seven transfers in parallel culture upon the hnedia 
indicated 
[Acidity and oxalate radical expressed in cubic centimeters oiNjio sodium hydroxid required to neutralize 
50 c. c. of Czapek's solution containing 5 per cent of cane sugar, after growth for 10 days] 
Culture No. 
Czapek’s 
solution. 
Raulin’s 
solution. 
Wort agar. 
Beef-peptone 
agar. 
Average. 
Comparison 
of 10 days’ 
growth from 
Table I. 
Acid¬ 
ity. 
Oxa¬ 
late. 
Acid¬ 
ity. 
Oxa¬ 
late. 
Acid¬ 
ity. 
Oxa¬ 
late. 
Acid¬ 
ity. 
Oxa¬ 
late. 
Acid¬ 
ity. 
Oxa¬ 
late. 
Acid¬ 
ity. 
Oxa¬ 
late. 
142. 
165.18 
190. 62 
150- 89 
192.58 
120. 57 
135 - 30 
125-57 
142.22 
143-05 
165. 23 
142.85 
155- 82 
2469.4. 
69-35 
67.90 
72-85 
86.18 
7 i-13 
68.40 
112. 29 
74-32 
80.95 
74. 20 
103.15 
94-35 
4047 . 
in. 
69.77 
82.49 
46.66 
98. 76 
71.04 
84.52 
56. 78 
100.98 
53-70 
73 - 76 
39 - 76 
89. 88 
65.80 
83-51 
56 - 54 
100. 98 
65.08 
81.07 
49 - 93 
97 - 65 
80. 52 
94 * 72 
4049_/. 
46.26 
48.36 
85.12 
58.52 
31. 81 
48.88 
62.99 
56 . 54 
56- 54 
53-07 
69.30 
59 - 41 
2766. 
33-15 
40.74 
80.50 
107.66 
49 - 85 
67.40 
43-27 
56.30 
51.69 
68. 02 
53-10 
62. 77 
40.28 
53-39 
45.18 
65.92 
54 * 53 
50.62 
38. 70 
40.00 
65. 40 
62.96 
49 - 73 
49 - 73 
52.41 
56 . 05 
2580. 
73 - 45 
77. 28 
50.86 
67.16 
38 . 23 
54-32 
53-98 
66.14 
49-57 
63.90 
28.14 
7 - 33 
45 -i 8 
17.28 
23-95 
39 - 76 
63.02 
55-30 
22.04 
35 - 56 
34 - 29 
43 - 95 
26. 64 
40. 73 
4030.1. 
11.16 
21.48 
11. 16 
4-43 
15-80 
11. 08 
13- 22 
5.58 
18. 31 
A study of Table II shows a somewhat higher acid production for 
cultures propagated upon the Czapek’s and Raulin’s solutions than for 
those given upon wort and beef-peptone agar. In spite of occasional 
contrasting figures, the entire table fails to show any marked increase or 
decrease in acid-producing power by the treatment. This experiment 
tends to the conclusion that there are many strains or varieties of black 
Aspergillus spp. which differ .markedly in the production of this reaction. 
These differences have persisted through many repetitions of the work 
with certain forms. Some of these forms, notably some of those pro¬ 
ducing the largest quantities of oxalic acid, have been in continuous 
culture by one of the writers for six years. Whether these strains would 
continue to produce oxalic acid iri the same quantity if cultivated for a 
longer period is not known. The mutants described and distributed by 
Schiemann 1 (3534-a, 3534-b, and 3534-c) differ from each other in the 
quantity of acid produced. This difference is accompanied by a differ¬ 
ence in color on the part of two of them, A. fuscus and A. cinnamomeus. 
In the case of A. niger, var. altipes, the strain as studied in this laboratory 
has lost the single'morphological difference—long stalks—originally de¬ 
scribed; hence, at present it is not distinguishable from our Amsterdam 
1 Schiemann, Elisabeth. Op. cit. 
