Jan. 17, 1916 
Plenodomus fuscomaculans 
749 
each dish. The various combinations employed, and the dilutions pres¬ 
ent in the culture, are indicated in Table XXIII. In every instance the 
concentration given shows the amount of the chemical that was present 
in the culture. The experiment was done in quadruplicate. 
Table XXIII .—Effect of quality of food: Test with nitrogen and carbon compounds 
Stock: solution of minerals plus— 
Carbon. 
Nitrogen. 
Number of 
pycnidia. 
Growth. 
Malic acid, Mjioo 
Glycerol, Mjioo. . 
Maltose, Mjioo ... 
Filter paper. 
Peptone, 0.02 per cent 
100 
60 
o 
Scant. 
Strong. 
Strong. 
No growth. 
Malic acid, Mjioo . 
Glycerol, Mjioo, .. 
Maltose, Mjioo. _ 
Filter paper. 
•Asparagin, Mjioo , 
None. 
Scant. 
Strong, 
None. 
Malic acid, Mjioo. 
Glycerol, Mjioo . .. 
Maltose, Mjioo . 
Filter paper.___ 
jbeiicm, .MI600 
5 Scant, 
o Scant. 
25-50 Strong. 
. None. 
Malic acid, Mjioo. 
Glycerol, Mjioo. . . 
Maltose, Mjioo . 
Filter paper. 
Potassium nitrate, Ml500. 
None. 
None. 
Fair. 
Scant. 
Malic acid, Mjioo 
Glycerol, Mjioo. . 
Maltose, Mjioo ... 
Filter paper. 
10-20 
o 
o 
10-15 
Fair. 
Scant, 
Fair. 
Fair. 
Peptone. 
Asparagin, M/500. 
Leucin, Mj6oo . 
Potassium nitrate, M/500 
i-5 
o 
o 
o 
Scant. 
Scant. 
Scant. 
Scant. 
This experiment shows that nitrogen, as previously shown for carbon, 
may be taken from widely different classes of compounds. The avail¬ 
ability of any particular nitrogen compound is largely determined by 
the associated carbon compound. For instance, peptone, which carries! 
available carbon, gave a large number of pycnidia with malic add, but 
none with maltose. Asparagin, which gives the best growth and the 
greatest number of pycnidia with maltose, gave no pycnidia with malic 
acid. Glycerol, which seems on the whole to be a poor carbon source,, 
gave with peptone strong pycnidium production, but with other nitrogen 
compounds behaved indifferently. As a further complication, peptone 
is able to serve both as nitrogen and as carbon source. Leucin gave 
poor growth with all carbon compounds except maltose, and a compari¬ 
son of its behavior with that of asparagin, which is a compound of the 
same class, is interesting. 
