226 Transactions of the Royal Microscopical Society. 
Mr. Fremy investigated the nature of this agent, and has 
ascertained that it is composed of two colouring principles, one a 
yellow, the other a blue; the former he has called phylloxanthin, 
and the latter phyllocyanin. Both these principles have been 
isolated by Mr. Fremy, who has also endeavoured to show that the 
yellow colour of blanched and very young leaves is due to the 
presence of a body which he has termed phylloxanthein, and which 
is coloured blue by the vapour of acids. The same result occurs in 
the discoloration of phyllocyanin; hence it would seem that this 
phyllocyanin is not an immediate principle, but that it is formed 
by the alteration of phylloxanthein, and indeed the spectroscopic 
observations that have of late years been carried on in relation to 
this subject, I am sure I may say by Mr. Sorby, tend to show that 
chlorophyll is more complex than Mr. Fremy considered, as the 
substances he treats of were probably only products of decomposi- 
tion by acids. 
The various shades of green seen in the organs of plants depend 
upon very different causes; partly upon the nature of the chlor- 
ophyll, whether it is pure, or more or less mixed with the yellow, 
blue, or brown products of its decomposition—see Mr. Sorby’s 
paper “On the Colours of Leaves at different Seasons of the 
Year;” partly upon the quantity of chlorophyll in the individual 
cells, partly on the thicker or looser arrangement of those cells, as 
on the under sides of leaves, which are generally of a lighter green, 
depending on the intercellular spaces which are there present, and 
which reflecting the light, white, thus mix with and diminish the 
intensity of the green. 
When any form of chlorophyll is treated with ether or alcohol, 
the colour is abstracted, while the organized forms, the corpuscles, 
&e., remain, so that true chlorophyll is really only a soluble sub- 
stance, dyeing the bodies called chlorophyll granules, &.; but the 
various degrees of solubility depend greatly on the presence of 
other substances, for instance, in the case of such evergreens as 
laurel, ether takes hardly any effect, but alcohol thoroughly dis- 
colours the leaves, whilst pyrethrum, a perennial, is hardly acted 
upon at all by alcohol, but ether takes great effect. 
If these solutions are evaporated to dryness, under the ex- 
hausted receiver of an air-pump, a green fatty matter is left, which 
forms soaps in combination with the alkalies. If this is again dis- 
solved in ether, and mixed with water, and the ether evaporated, 
small greasy globules are obtained, and similar globules are sepa- 
rated from the alcoholic solution at a freezing temperature. If the 
alcoholic tincture be mixed with water, and the alcohol evaporated 
by heat, part of the fatty substance is precipitated; the remaining 
solution is coloured a brown yellow, and has a characteristic smell, 
like that of black tea. It is soluble in the volatile and fixed oils, 
