48 Elementary Work in Botany. 



made tip of little sacs called cells which, are filled with wet 

 starch. This starch was made in the leaves of the potato 

 plant and stored in its tnbers for the nse of the buds in 

 their first growth the next season.* 



The nse of starch stored in tubers, then, is similar to 

 that of starch stored in cotyledons; or, as endosperm, within 

 the seed coat outside the embryo. It feeds the plant in its 

 growth from a practically leafless condition (as a bud on a 

 tuber or an embryo in a seed) until it has leaves with which 

 to make its own starch. Starch is frequently stored in stems 

 above ground. Sago, a kind of starch, is obtained from the 

 pith of the sago palm. Starch and sugar are stored in such 

 roots as sweet-potatoes, yams, beets, etc. 



*The teacher might profitably have ready for this exercise a piece of clean 

 muslin two feet square, a large tin grater, two tin pans, a bucket and something 

 with which several pounds can be accurately weighed. 



Take two pounds of the larger pieces of potato (used by the pupils but not 

 inked), and grate about half of each piece into the pan which should be half full 

 of water. Continue grating until just a pound is left. Stir the grated potato 

 until it is mixed with the water. Place the cloth over the empty pan and pour the 

 grated potato and water into the cloth-lined pan; bring up the corners of the 

 cloth and hold them with the larger part of the cloth in the left hand while you 

 knead under water the starch bag thus formed until you think all the starch 

 is out. Take the bag out and squeeze it over the pan until it does not drip. Then, 

 if you wish to be accurate, put water in the first pan and try to get out more starch 

 by thorough but not too energetic kneading. When the starch has settled so as 

 to leave the water clear, pour off the water and set the pan on edge to drain, and 

 leave it until the starch is dry (some time the next day). Put the celulose which 

 was left in the cloth on a plate to dry. The dry starch and the celulose should be 

 weighed. The sum of their weights taken from one pound shows the amount of 

 water in a pound of potato. This work would make a separate exercise. 



