202 THE UNIVERSITY SCIENCE BULLETIN. 



In the leaflet the pahsade cells are full of starch grains. These 

 grains are definite in shape and about three microns in diameter. 

 Potassium iodide-iodine and chloroiodide of zinc are the indicators 

 used. 



Material gathered early in the morning showed much starch in 

 the stem, but less in the green parts; that gathered at night showed 

 an abundance in the green parts. 



Protein. When Millon's reagent is applied to sections they 

 immediately begin to turn pink, which color deepens on standing 

 or on heating. Protein is thus found to be present in the pith, 

 medullary rays, pericycle, cortex, and especially much in the food- 

 conducting tissues of the stem. In the petiole the same is true 

 except that the pith contains very little. It is uniformly present 

 in the leaflet. Potassium iodide-iodine confirms these indications. 

 Material collected in the early morning and at night seems to con- 

 tain the same amount. 



Mucilage. Mucilage is present in the stem, as shown by 

 methylene blue. Sections soaked in water still give the mucilage 

 reaction, showing that it is not completely soluble in water, but 

 might swell. A section of petiole was taken, mounted in alcohol, 

 a distance measured, then water applied at one side of the cover 

 glass. The cells immediately began to swell, the measured portion, 

 sixty microns, swelling to seventy-five microns in a few minutes. 

 The cells could be seen to round out. The mucilage was found to 

 be more abundant near the edge of the section than in farther. 

 The leaflet shows mucilage also. This occurrence of mucilage is 

 interesting, as it is from species of Astragalus that the gum trag- 

 acanth of commerce is obtained. 



Oil. Sudan III shows minute droplets of oil, in the pith cells 

 especially. Sections soaked in ether overnight show less of this. 

 Pieces of stem and leaf were steamed, the stem being collected on 

 cover slips. These were first thoroughly cleaned with ether and 

 handled with forceps. After staining with Sudan III no drops of 

 oil are seen; therefore I conclude no volatile oils are present. 



Tannin. Tannin is indicated by a purple color appearing when 

 ferric chloride is added to sections containing it. No indication 

 of it could be discovered in stem, petiole or leaflet. The test was 

 repeated several times, always on fresh material. 



Resin. Sections were soaked in a saturated aqueous solution 

 of copper acetate, which turns resin green. Observations taken 



