108 THE UNIVERSITY SCIENCE BULLETIN. 



tate of cuprous oxide began to form after boiling for a minute or 

 so; and upon further boiling a copious precipitate formed. Other 

 sections mounted in Fehling's solution on hollow-ground slides 

 were placed in the electric oven and examined daily. After twenty- 

 four hours cuprous oxide crystals had formed, and for three days 

 thereafter the number of crystals gradually increased and the 

 globules disappeared. The slow reduction of two tests suggest 

 the presence of glucosides in these globules. 



The presence of resin was not indicated in sections which had 

 been left in concentrated copper acetate solution for three weeks. 



The blue stain characteristic of mucilage did not develop in 

 free-hand sections placed in a solution of methylene blue in equal 

 parts of alcohol, glycerine and water. 



Tannin was not demonstrated in sections mounted in ferric 

 chloride. 



A few crystals of cuprous oxide were formed in the cells of the 

 epidermis, and also in cells of the collenchyma, parenchyma, and 

 starch sheath of the primary cortex, in sections mounted in Feh- 

 ling's solution and heated just to the boiling point. Crystals of 

 cuprous oxide were also formed in the phloem cells of the primary 

 vascular bundles. The presence of reducing sugar, probably grape 

 sugar, was thus indicated by the immediate reduction of the 

 reagent without boiling. 



Starch was not generally foimd in the starch sheath; a slight 

 amount of starch was foimd in region II; a few cells of the starch 

 sheath in the main axis of the stem contained much starch. 



The contents of cells of the phloem of the primary vascular 

 bundles and the phloem of the anomalous tissue stain red in sec- 

 tions left in Millon 's reagent for several hours in the electric oven. 

 A yellow stain of these cell contents appeared in sections mounted 

 in concentrated nitric acid, and the yellow color deepened when a 

 drop of ammonium was added. The results of the two tests in- 

 dicate the presence of proteins. 



Large spherical aggregates of calcium oxalate crystals are pres- 

 ent in the starch sheath cells, in the outer rows of cells of the peri- 

 cycle, and in the pith cells, in all regions of stem; but are especially 

 abundant in region III and below (fig. 9, s). The starch sheath 

 cells and a few collenchyma cells of the primary cortex in region II 

 are filled with masses of the crystals. Only one aggregate of 

 crystals occurs in a single cell. A few of the pith cells in regions 

 III and IV and the main axis contain a few or quite a number of 

 f ingle crystals (fig. 9, t). There are abundant clusters of these 



