CHLOROPHYLLS. 101 



Its color is also changed to blue or green by other strong acids, but it 

 is not affected by dilute solutions of the alkalies. It has not yet been 

 obtained in sufficient quantity for complete analysis. 



Chlorophylle, 



This is the green coloring matter of plants. It is more widely dif- 

 fused than any other coloring matter in the vegetable world, and it 

 apparently constitutes exclusively the coloring principle of all the green 

 parts of the higher plants without exception. Its exact chemical con- 

 stitution has not been fully determined, but it is considered to be a 

 nitrogenous substance, and Mulder has given it the formula C 9 H (J N0 4 . 

 It is certain that iron is essential to its production, as plants artificially 

 cultivated without the access of this substance, grow up in a blanched 

 or chlorotic condition ; and their green color may afterward be restored 

 by the supply of moisture containing a ferruginous salt. 1 



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

 is under the influence of this substance, together with that of the solar 

 light, that the inorganic ingredients of the soil and the atmosphere are 

 deoxidized and combined in the form of an organic carbo-hydrate. The 

 process of vegetation proper, that is, the production and accumula- 

 tion of organic material in the form of starch, sugar, cellulose, woody 

 fibre, and the substance of various vegetable tissues, is inseparably 

 dependent on the presence and action of Chlorophylle. At the same 

 time, in order to produce this effect, the Chlorophylle must constitute a 

 part of the living vegetable cell ; for the coloring matter alone, if ex- 

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

 conditions, such as the access of air, sunlight, warmth, and moisture, 

 known to be essential to the work of production, is found to be incapable 

 of forming organic matter out of water and carbonic acid. Its func- 

 tion, therefore, is not that of a simple chemical reagent, but that of an 

 active constituent of the living vegetable organism. 



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

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

 in the form of distinct rounded grains, frequently arranged in definite 

 figures or patterns in the cavity of the cell. It may be extracted by the 

 action of alcohol or of ether, and retains its green color in solutions of 

 these substances. It disappears previously to the shedding of the leaves, 

 when they cease to perform the act of vegetation, and is usually replaced 

 by a few grains of red or yellowish color. 



1 Mayer, Lehrbuch der Agrikultur-Chemie, Band i. pp. 51, 265. 



