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