June i, 1925 H-ion Concentration and Pigment in Fusaria 1013 
Table I.— Color h intensity , and difusibility of pigment produced by different 
species of Fusarium at different hydrogen-ion concentrations , and volumes of 
adjusting reagents ( c . c. 0.2 normal HC1 and NaOH) required to maintain the 
initial Ph value of the solution constant in dextrose solutions —Continued 
Organism 
Initial 
Ph 
Adjusting reagent 
Color of pigment 
HC1 
NaOH 
F. redolens Sher.... 
3.0 
12 
0 
Flesh pink 
Do...._ 
4.0 
0 
4 
Flesh pink. 
Do_ 
5.0 
0 
10 
Capucino orange (diffusible). 
Do__ 
6.0 
0 
30 
Colorless. 
Po--- 
7.0 
0 
60 
Do. 
Do_ 
7.5 
0 
90 
Do. 
Fusarium sp. (15)_ 
3.0 
11 
0 
Flesh pink. 
Do___ 
4.0 
3 
0 
Do. 
Do.. 
5.0 
0 
5 
Ivory. 
Do... 
6.0 
0 
16 
Colorless. 
Do___ 
7.0 
0 
40 
Do. 
Do__ 
7.5 
0 
90 
Do. 
F. malli Taub... 
v 3.0 
15 
0 
Pale flesh. 
Do__ 
4.0 
5 
0 
Flesh pink. 
Do..__ 
5.0 
0 
4 
Cinnamon (diffusible). 
Do_„_ 
6.0 
0 
17 
Colorless. 
Do.__ 
7.0 
0 
60 
Do. 
Do__ 
7.5 
0 
100 
Do. 
F. anaustum Sher 1_____ 
3.0 
6 
0 
Flesh pink. 
Do_ 
4.0 
0 
18 
Vinaceous. 
Do_ 
5.0 
0 
26 
Shrimp pink. 
Do_... 
6.0 
0 
35 
Colorless. 
Do_ 
7.0 
0 
45 
Do. 
Do__o 
7.5 
0 
80 
Do. 
F. loncheceras Sid __ 
3.0 
6 
0 
Salmon pale. 
Do___ 
4.0 
0 
9 
Vinaceous, dark. 
Do........_ 
5.0 
0 
20 
Shrimp pink. 
Do____ 
6.0 
0 
35 
Colorless. 
: do___ 
7.0 
0 
70 
Do. 
Do_ 
7.5 
0 
130 
Do. 
F. culmorum (W. Smith) Sacc_ 
3.0 
16 
0 
Begonia rose (diffusible). 
Do_ 
4.0 
0 
3 
India red (diffusible). 
Do___ 
5.0 
0 
6 
Victoria Lake (diffusible). 
* Do_ 1 _ 
6.0 
0 
23 
Colorless. 
Do_ 
7.0 
0 
75 
Do. 
Do___ 
7.5 
0 
120 
Do. 
F. moniliforme Shel_ _ 
3.0 
5 
0 
Flesh (diffusible). 
Do_ 
4.0 
' 0 
4 
Hydrangia pink (diffusible). 
Do__■_ 
5.0 
0 
10 
La France pink (diffusible). 
Do.__ 
6.0 
0 
25 
Colorless. 
Do_ 
7.0 
Q 
55 
Do. 
Do__ 
7.5 
0 
90 
Do. 
F. radicicola Wr_ 
3.0 
21 
0 
Flesh (diffusible). 
Do......... 
4.0 
11 
0 
Scarlet red (diffusible). 
Do____ 
5.0 
5 
0 
Peach red (diffusible). 
Do_ 
6.0 
0 
31 
Colorless. 
Do_ 
7.0 
0 
75 
Do. 
Do_..... 
7.5 
0 
125 
Do. 
F. martii Ap. et Wr_ ... 
3.0 
9 
0 
Apricot orange (diffusible). 
Do_ 
4.0 
5 
0 
Nopal red (diffusible). 
Do_ 
5.0 
1 
0 
Maroon dark (diffusible). 
Do_ 
6.0 
0 
36 
Colorless. 
Do___j__ 
7.0 
0 
80 
Do. 
Do_ 
7.5 
0 
130 
Do. 
EXPLANATION OF RESULTS 
The results in Table I indicate that 
the relative hydrogen-ion concentra¬ 
tion of culture media of dextrose solu¬ 
tions is possible to initiate or inhibit 
the development of pigment in Fusaria. 
Moreover, the color, intensity, and 
diffusibility of the pigment may be 
controlled by the relative hydrogen-ion 
concentration of the surrounding solu¬ 
tion. It becomes evident, therefore, 
that the ability of the different species 
to form a certain pigment depends, 
either wholly or in part, on the relative 
acidity of the culture media. Con¬ 
centrations of hydrogen-ion higher than 
P H of 3.0 or lower than P H of 7.0 were 
found to inhibit the development of 
pigment, practically, in every case. 
The optimum hydrogen-ion concentra¬ 
tions for the development of pigment 
lie between P H of 4.0 and 5.0. 
The nature and extent of the changes 
produced on the initial P H value of the 
different cultures by the Fusaria em¬ 
ployed, as they are measured by the 
volume of the adjusting reagent re- 
