On the Colour of Leaves of Plants and their Autumnal Changes

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                                It has been pointed out, that when the alcoholic solution 
is kept for some days, it undergoes certain changes and 
amongst these is the deposition of a reddish sediment.
This precipitation is mainly due to the presence in the 
sap of most leaves of a small quantity of acid, <s>and <\s>
which becomes in due course transferred to the alcohol 
employed in the extraction of the chlorophyll and as the 
alcoholic solution evaporated, the acid present becomes 
concentrated and thus relatively increased. Now this 
deposition may <s>hastened <\s> be hastened and indeed brought about almost 
at once by the addition of a small quantity of a solution 
of an organic acid, such as tartaric acid.
If a little of this reddish brown precipitate be examined 
under the microscope in a moist state, it is found to consist 
of granular masses mostly of a yellowish and some of a 
brownish red <s>line; If a little of the granular matter <\s> hue and if it be dried 
on a glass slide and a minute quantity of a 10 per cent 
solution of tartaric acid <s>be<\s> added and <s>the granular matter it be <\s>
be then again dried, it will now have assumed a much deeper and 
in some parts, a decidedly reddish colour. This appearance is 
of importance, as will be made apparent hereafter.
I will next record the results of the application of certain 
reagents to small quantities of the chlorophyll solution 
obtained from the green leaves of the Capucin arum and 
other plants, limiting the reagents used chiefly to those 
which are known to occur in the leaves of plants, both 
deciduous and perennial.
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Manuscript details

Arthur Hill Hassall
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Cite as

On the Colour of Leaves of Plants and their Autumnal Changes, 1892. From The Royal Society, AP/69/1



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