104 PHYSIOLOGICAL CHEMISTRY. 



the orange, between C and D ; another at the beginning of the green, 

 on the left of E ; and a third, wider than the others, but very faint and 

 ill-defined, at the termination of the green, between E and F. In the 

 spectrum of chlorophylle, the yellow of the spectrum appears in its 

 proper place and w~ith nearly its natural hue. The light, also, extends 

 beyond the green, throughout the blue, and a little into the com- 

 mencement of the indigo. 



Chlorophylle is of the first importance in vegetable physiology, as it 

 is under the influence of this substance, and that of the solar light, 

 that the inorganic ingredients of the soil and the atmosphere are 

 deoxidized and combined to form a carbo-hydrate. The process of 

 vegetation proper, that is, the production and accumulation of organic 

 material in the form of starch, sugar, cellulose, and the substance 

 of various vegetable tissues, is inseparably dependent on the action of 

 chlorophylle. But to produce this effect, the chlorophylle must con- 

 stitute a part of the living vegetable cell. The coloring matter alone, 

 extracted from the chlorophylle-holding cells, and placed under all other 

 conditions, such as air, sunlight, warmth, and moisture, known to be 

 essential to the work of production, is incapable of forming organic 

 matter out of water and carbonic acid, Its function is not that of a 

 simple chemical reagent, but that of an active constituent of the living 

 organism. 



Chlorophylle is produced, in the interior of the vegetable cell, some- 

 times as a uniformly diffused mass. Usually, however, it is deposited 

 in rounded grains, frequently arranged in definite figures or patterns 

 within the cell. It may be extracted by alcohol or ether, and retains 

 its green color when in solution in these substances. It disappears 

 previously to the shedding of the leaves, when they cease the act of 

 vegetation, and is usually replaced by grains of a red or yellowish 

 color. 



