GENUINE STARCH FACTORIES. 



721 



n e r 



Fig. 0. — PoHTioN OF Leaf Magnified, 



ILLUSTKATIKG PiIOTO-SyNTIIESIS. 



Fig. 5 is an attempt to present the above statements as to pho- 

 to-synthesis in plants in such a form that it may appeal to the eye 

 of the reader. A bit of maple twig is shown with one leaf in posi- 

 tion. Passing up the stem in the 

 3'onng wood is the crude sap from 

 the soil to the leaf. There is a 

 downward flow of elaborated sap 

 in the inner bark also repre- 

 sented. Solar energy is indi- 

 cated by the wave lines as play- 

 ing upon the upper side of the 

 leaf, while the direction of the 

 carbon dioxide is shown by the 

 dotted lines entering from both 

 above and below the leaf. Wa- 

 ter of transporation is indicated 

 as being given off, and upon a 

 dry, hot day this is considerable, 

 which, as it vaporizes in the tis- 

 sue, tends to keep the latter cool. 

 Lastly, with the formation of 

 starch there is the escape of oxy- 

 gen set free from the broken molecule of carbon dioxide or water 

 or both in the formation of the starch. 



Fig. 6 is a similar attempt to show the process of starch forma- 

 tion with the use of a portion of the leaf in section as it might 

 appear under the microscope. The under portion of the leaf is 

 seen as having openings in the skin, through which the gases and 

 vapors pass, and the middle portion above shows the porous nature 

 of that part that is most active in synthesis. The small oval bodies 

 in all the cells, except those of the upper and under epidermis, 

 represent the chlorophyll granules, the special seat of the special 

 activities which result in the formation of the carbohydrate, famil- 

 iar to all as starch. To the right is a leaf vein, through which 

 the crude sap (c. s.) reaches the synthetic cells, and the elaborated 

 sap (e. s.) descends to places Avhere it is needed for growth or for 

 storage. 



"With the above facts in mind, there is no wonder at the activity 

 that may reside in a field of corn during a bright day in August. 

 Starch is being made almost by the ton daily, and, if the conditions 

 favor, the next month will find a rich harvest for the husbandman 

 who has assisted in supplying the conditions for the desired output 

 of the leading carbohydrate. 



The genuine starch factories of the world are exceedingly 



VOL. LYI.- 57 



