PLATE 17 
Fig. A.—Green tobacco leaf from Treatment I, Red Lion, Pa., 1914, killed in absolute 
alcohol and showing idioblasts of calcium oxalate and minute, scattered, single crystals 
of an undetermined substance, but no grain. Photographed with polarized light. 
X 65.5. 
Fig. B.—Representative sample of the poor burning 1909 Pennsylvania tobacco. 
Photographed with polarized light. X 65.5. 
Fig. C.—Flue-cured tobacco. Poor-burning. Photographed with polarized light. 
X 65.5. 
Fig. D.—Connecticut Broadleaf tobacco. Good burning. The brown coloring mat¬ 
ter concentrated in the grain partially masks their structure in some cases. Photo¬ 
graphed with polarized light. X 65.5. 
Fig. E.—Fermented tobacco from Treatment I, Red Lion, Pa., 1914. Poor burning. 
Photographed with polarized light. X 65.5. 
Fig. F.—Fermented tobacco from Treatment III, Red Lion, Pa., 1914. Good burn¬ 
ing. The brown coloring matter concentrated in the grain partially masks their 
structure in some cases. Photographed with polarized light. X 65.5. 
Fig. G.—Tobacco from Treatment I, Red Lion, Pa., 1914. Cured only. Photo¬ 
graphed with polarized light. X 65.5. 
