436 
LEWIS KNUDSON 
Fig. 4. I. Galactose .025 mol. 
2. " .025 " -|- mannose .025 mol. 
3. Mannose .025 mol, 
4. " .025 " + glucose .025 mol. 
5. " .025 " + saccharose .025 mol. 
1. Galactose .025 mol. 
2. Mannose .025 mol. 
3. Mannose .025 mol. + galactose .025 mol. 
4. Mannose .025 mol. + glucose .025 mol. 
5. Mannose '.025 mol. + saccharose .025 mol. 
6. Glucose .025 mol. 
7. Saccharose .025 mol. 
8. Pfeffer's solution alone — no sugar. 
Both with wheat and with peas it was found that the toxicity of 
mannose is antidoted by either glucose or saccharose. Mutual an- 
tagonism was not found between galactose and mannose. The plants 
grown in the other solutions were in every way normal. Representa- 
tive cultures are shown in Figs. 3 and 4. 
Discussion. — The hexose sugars glucose, mannose, and galactose 
are stereoisomers. All of them are used by various fungi, and 
mannose is as readily fermented by yeasts as is glucose. Galactose, 
