Oct., 1922] YOUNG AND BENNETT FUNGI IN CULTURE MEDIA 
Table i 
No. of 
Solution 
Composition of Culture Solution 
Fusarium 
oxy- 
sporum. 
Dry 
Weight in 
Grams* 
pH 
Asper- 
gillus 
ntger , 
Dry 
Weight in 
Grams* 
T T 
pH 
Rhizopus 
nigricans, 
Dry 
Weight 
in 
Grams* 
pH 
I 
Richards solution 
.2094 
•5450 
2.4 
.2015 
2.6 
2 
Richards solution, KNO3 replaced by 
Ca(lN03)2 
.2494 
6.4 
.8070 
4.8 
.2747 
3 
Richards solution, KH2r04 replaced by 
JNa2Hr(J4 
•2575 
6.4 
■3841 
2.6 
• 1 843 
4 
Richards solution, KHol U4 replaced by 
KLl 
.0736 
4.4 
.1641 
.0925 
5 
Richards' solution, KNO3 replaced by KCI 
INO 
.0250 
4.6 
i\o 
growth 
growth 
6 
Richards solution, sucrose replaced by dex- 
trose 
.1932 
5-6 
.3700 
3-6 
.1234 
7 
T>'11J1j_* 1 It 1 
Richards solution, sucrose replaced by mal- 
tose 
.3124 
v'S.4 
•3560 
2.4 
•1540 
8 
Richards' solution, sucrose replaced by lac- 
tose 
.0404 
5-0 
.2640 
4.0 
9 
Richards' solution, sucrose replaced by g'lyc- 
erin 
.1163 
4.2 
.0406 
10 
Richards' solution, sucrose replaced by raffi- 
nose 
.2900 
2.4 
.1000 
II 
Richards' solution, sucrose replaced by galac- 
tose 
•2345 
0.0 
.4240 
2.6 
.1560 
12 
Richards' solution, sucrose replaced by levu- 
lose 
.1132 
4.2 
.1690 
3-0 
.0825 
13 
Richards' solution, sucrose replaced by man- 
nose 
.2146 
5-8 
.4040 
3-2 
.1420 
14 
Richards' solution, iron omitted 
•2458 
6.4 
•7243 
3.6 
15 
Richards' solution, plus 15 mg. ZnSOi 
.2432 
6.4 
•713I 
16 
" 10 " " 
.2243 
6.2 
•9043 
2.4 
17 
" 5 " " 
.2186 
6.3 
.8078 
2.4 
18 
" << J << 
.2506 
6.6 
.8124 
2.4 
19 
" 0.5 " " 
.6312 
2.8 
20 
Coons' cheap synthetic solution 
.0500 
3-8 
* Average for three cultures. 
the available carbon is completely used up. Our results in this connection 
are contrary to those of Graves (6), who states that a thermolabile "staling" 
substance is produced which stops the growth of the fungus. 
The reaction of the culture solution in which Fusarium oxysporum was 
grown continued to become acid until a hydrogen-ion concentration of pH 
3.6 was reached, then turned alkalineward, and growth continued until all 
the organic compounds were broken up and a hydrogen-ion concentration 
of pH 84 was reached. 
Zinc sulphate stimulated growth in the case of Aspergillus niger but 
not in that of Fusarium oxysporum or of Rhizopus nigricans. 
Since calcium proved to be so beneficial when placed in the nutrient 
solution for the growth of the organisms used in the preceding experiment, 
it was thought important to determine whether this same relation would 
hold for a number of parasitic organisms. An experiment was planned 
using Richards' solution as a medium in one series and the same solution 
