80 CELL CONTENTS. 



Acetic Acid first. If it has no effect, draw it off, arid apply Hydro- 

 chloric Acid. Make sure the acids reach the crystals and particu- 

 larly observe the effect on any which may have floated out of the 

 cells. 



Tests for Calcic Phosphate and Calcic Sulphate are given in 

 Poulsen and Trelease's Botan. Micro-Chemistry, p. 96 ; Zimmer- 

 mann's Microtechnique, pp. 64, 62. 



THE STUDY OF GROUP I. Raphides will be reserved until later 

 in the outline, in connection with an examination of growing roots, 

 in which these crystals are found in abundance near the tip. 



Illustration Eighth : CYSTOLITHS. These are the concre- 

 tions composed of cellulose and a salt of lime, and are found 

 chiefly in the epidermal regions of certain Urticaeeae. 



Illustration: Leaf of Ficus ELASTICA (one of the " C<i<mt 

 chouc Trees.) 



PREPARATION : Select a piece from the upper part of a leaf 

 and mount the thin transection in water. See p. 16. 



OBSERVE: 1. The upper JZpiderrnis, a layer of small color- 

 less cells on the upper surface of the leaf. 



2. The Hypodermal layer of larger, also colorless cells just 

 beneath the upper Epidermis. 



3. Larger cells at intervals in the hypodermal layer contain- 

 ing the concretions the Cystoliths, attached to the peripheral side 

 of the cell by a stalk. 



Apply to this the preceding test for crystals, and demonstrate 

 what salt of lime is present. 



After the test has been completed, and the acid washed out, 

 apply strong iodine, and observe the skeleton of cellulose re- 

 maining in the Cystolith. DeBary, p. 44, 104-105; Bessey, p. 11; 

 Vines' Text Book of Bot., p. 108; Zimmermann's Microtechnique, 

 p. 61. 



Inulin. 



Illustration Ninth : A substance of the same chemical com- 

 position as starch and found dissolved fu the cell sap of many 

 plants: Dahlia root, or Jerusalem Artichoke. 



PREPARATION: Make thin transections of a piece of /><ilil'm 

 root that has been left for some days in strong alcohol or glycerin. 



