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colour of the leaf. On washing the leaves with a little 
ether the film of fatty matter disappears instantly, the leaves 
then appearing green like ordinary leaves. The ether leaves 
on evaporation a white semi-crystalline fatty residue which 
melts at a temperature much lower than that of boiling 
water, and is partly soluble in dilute alkaline lye boiling, so 
that it probably consists in part of some fatty acid. The 
leaves after washing with ether do not differ in appearance 
from other leaves. The alcoholic and ethereal extracts of 
these leaves show however a peculiarity, as regards the 
chlorophyll contained in them, which I have not observed 
in any other green leaf extract, though the same thing may 
have been observed by others and recorded in one of the 
numerous memoirs on chlorophyll, the whole of which I do 
not profess to have read. If a few of the smallest and latest 
formed Eucalyptus leaves from the tips of the branches are 
extracted with ether a green solution is obtained which 
shows the usual absorption bands of ordinary unchanged 
chlorophyll. If however a little of the extract contained in 
a tightly corked test tube be kept in a dark cupboard for 
several days it gradually acquires a yellowish tint and now 
shows absorption bands coinciding with those of so-called 
‘ acid chlorophyll,’ that is, of the modification which is pro- 
duced at once by adding a few drops of an acid, such as 
acetic acid, to a solution of ordinary chlorophyll. The 
change in the spectrum produced by the action of acids con- 
sists in the disappearance of the chlorophyll band III, and 
the intensification of bands II and IV, which now more 
nearly approach band I in strength. An alcoholic extract 
of more fully developed but still quite fresh and vigorous 
leaves (I took for the purpose the pair next in order of de- 
velopment to those at the summit of the branch) showed 
the ordinary chlorophyll bands, though on attentive exami- 
nation band lY was found to be a little more defined than 
usual. After being kept in the dark however for 24 hours 
