Jan. 17* 1916 
Plenodomus fuscomaculans 
745 
It will be noticed that in nearly every case, even in low concentration 
of sugar, there was an increased growth following the addition of sugar. 
Filter paper and oat broth, which normally produce pycnidia, gave strong 
growth with saccharose, dextrose, and maltose, but no pycnidia. In 
the case of levulose M/50, the growth was not greatly increased, and one 
or two pycnidia appeared. This number is much less than the normal 
for filter paper alone. We may conclude that these sugars exert a repress¬ 
ing influence on pycnidium production, and at the same time augment 
vegetative growth. How this is brought about is difficult to explain; 
but in some way the ratio of the constituents was so altered that the 
limits for reproduction of some factor—e. g., reaction—or of some group 
of factors was exceeded. 
A more comprehensive experiment was performed in which a large 
number of carbohydrates was tested. Equal parts of the minerals of 
Raulin’s solution in 2 X concentration were added to various M/10 sugar 
solutions and to 2 per cent solutions of the polyoses whose molecular 
weight is not known. Each combination was set up in four capsules, 
using 10 c. c. per dish. The media were steamed on three successive 
days and inoculated with a drop of spore suspension for each dish. 
Table XXI gives the result of this experiment. 
Tabi^E XXI.— Effect of quality of food: Test with carbohydrates 
[Time, 2 months] 
Growth. 
Carbohydrate. 
Concentration. 
Size of 
colonies. 
Character. 
Form of 
fructification. 
Mm . 
Xylose (pentose). 
Maltose (disaccharose). 
Glucose (monosaccharose).. 
Mannose (monosaccharose). 
Galactose (monosaccharose) 
Levulose (monosaccharose). 
Arabinose (pentose). 
Sorbose (monosaccharose).. 
Sucrose (disaccharose). 
Raffinose (polysaccharose).. 
Lichenin (polysaccharose).. 
Dextrin (polysaccharose)... 
Inulin (polysaccharose).... 
Gum arabic (polysaccharose) 
Gum tragacanth (polysac¬ 
charose). 
Wheat starch (polysacchar¬ 
ose). 
Lactose (disaccharose). 
Erythrose (tetrose). 
Mj20 . 
Ml 20 . 
Mj 20 . 
Ml 20 . 
M/20 ...... 
M/20 . 
Ml 20 . 
Ml 20 . 
Ml 20 . 
Mf 20 . 
1 per cent. 
1 per cent. 
1 per cent. 
1 per cent, 
1 per cent, 
3-4 
3 
2 
2 
2 
1-2 
1-2 
2-3 
Compact. 
Compact. 
Compact. 
Compact. 
Compact. . .. 
Compact. 
Compact. 
Floccose. 
Compact. 
Floccose, very loose. 
Loose mat, cover¬ 
ing dish. 
Diffuse mat, cover¬ 
ing dish. 
....do. .. 
_do... 
.do. 
1 per cent 
Ml 20 . 
Mfeo . 
No growth 
No growth 
No growth 
Oidia. 
Oidia. 
Oidia. 
Oidia. 
Oidia. 
Oidia. 
Oidia. 
Pycnidia. 
Oidia. 
Mycelium. 
Second ary 
spores. 
Pycnidia. 
Pycnidia. 
Pycnidia. 
Pycnidia. 
17210°—16 - 3 
