The green colouring matter of the leaves and other parts of plants which is only developed when plants are grown in the light. So far as investigation has gone it would appear to be a magnesium compound of the formula Mg,C63HT2N46 or Mg,CBSH72N46, and there seems to be some relationship between it and the colouring matter of the blood. It is associated in leaves with two other colouring mattersviz., carotin, the substance which gives its colour to carrots, and xanthophyll, a substance of dark brownishred tint. Chlorophyll itself is stated to be a mixture of two substances, differing in their spectra and solubility in certain solvents.

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Definition of  CHLOROPHYLL