Oct 30,1916 Growth of Parasitic Fungi in Concentrated Solutions 257 
The spores were germinated and the fungi grown in solutions of cal¬ 
cium nitrate, potassium nitrate, sucrose, and glucose. Concentrated so¬ 
lutions were made of these substances, which were diluted down to the 
concentration desired in the experiments by the addition of distilled 
water to which a very little potato extract had been added. 
The weight normal method of Morse and Frazer (12) was followed in 
making up the solutions. 
The diffusion tension of the highest concentrations used in which the 
spores germinated and grew was calculated for the various compounds, 
taking into account, of course, the ionization of the salts. The data for 
calculating the percentage of ionization of the two salts were obtained 
from Jones's tables (8). The calculations of the percentage of ionization 
give probably only approximate values as the calculations are based on 
interpolations in most cases, and, moreover, some other substances were 
present which might influence the dissociation of the salts. The data thus 
obtained, however, probably offer a better basis for the comparison of the 
diffusion tensions of the two electrolytes and the two nonelectrolytes used 
in this study than the molecular concentrations given in the adjoining col¬ 
umns. The diffusion tension of the cane-sugar solutions was calculated 
from Morse and Frazer's determination of the osmotic pressure of a molec¬ 
ular solution of this substance at 25 0 C. From their work and from the 
determinations of Berkeley and Hartley (1) it seems quite probable that 
the values given are too low. The results obtained in growing fungi in 
the concentrated solutions of salts and sugars are given in Table I. 
Tabi^E I .—Highest concentrations (molecular) of calcium nitrate f potassium nitrate , 
sucrose , and glucose in which the fungi grew and the calculated diffusion tensions in 
atmospheres of these solutions 
Fungus. 
Glucose, 
Sucrose. 
Potassium 
nitrate. 
Calcium nitrate. 
Con¬ 
centra¬ 
tion 
(molec¬ 
ular). 
Diffu¬ 
sion 
tension 
(atmos¬ 
pheres). 
Con¬ 
centra¬ 
tion 
(molec¬ 
ular). 
Diffu¬ 
sion 
tension 
(atmos¬ 
pheres). 
Con¬ 
centra¬ 
tion 
(molec¬ 
ular). 
Diffu¬ 
sion 
tension 
(atmos¬ 
pheres). 
Con¬ 
centra¬ 
tion 
(molec¬ 
ular). 
Diffu¬ 
sion 
tension 
(atmos¬ 
pheres). 
Fusarium radicicola . 
1. 6 
038.9 
1.8 
47-4 
1. 6 
54 - 5 
O. 6 
27. 7 
Fusarium oxysporum . 
I. 6 
038.9 
1.8 
47-4 
1. 6 
54-5 
.6 
27.7 
Plenodomus destruens . 
2.4 
“58-3 
1.8 
47-4 
1. 6 
54 - 5 
* 7 
33*6 
Sphaeronema fimbriatum .... 
2. 6 
a 63. 2 
1.8 
47-4 
1. 6 
54*5 
•4 
19*5 
Diplodia tubericola . 
2. 6 
a 63. 2 
1. 6 
42. 1 
1. 8 
58.8 
• 7 
33*6 
Rhizopus nigricans (from 
strawberry) . 
1. 6 
a 63. 2 
.8 
27*5 
15*9 
Rhizopus nigricans (from 
O 
sweet potato). 
1. 6 
a 63. 2 
1. 6 
42. 1 
.8 
27*5 
•3 
15 * 9 
Botrytis cinerea . 
2. 6 
a 63. 2 
1.8 
47*4 
1. 6 
54*5 
.6 
27.7 
Sclerotinia cinerea . 
a KS. 
I. A 
47. 6 
. 6 
27 . 7 
Sphaeropsis malorum . 
2. 6 
a 63. 2 
1.8 
47-4 
*T 
i. 6 
54-5 
.6 
27.7 
Glomerella cingulata . 
4 i .3 
“ 39-3 
29. I 
a No higher concentrations used. 
