68 Schunck . — The Chemistry of Chlorophyll . 
rophyll is very sensitive to the action of acids. On adding an 
acid, however weak, to a solution of chlorophyll, the colour 
of the solution changes more or less rapidly from bright green 
to olive, and the original colour cannot be restored, indicating 
a complete alteration, though not of course an entire destruc- 
tion, of the colouring matter. Berzelius, Mulder, Morot, and 
Fremy, who all employed processes for preparing chlorophyll 
involving the use of hydrochloric acid, really obtained pro- 
ducts resulting from its decomposition, and it is therefore 
unnecessary to make any further reference to their labours 
at present. 
A few simple experiments should convince an unpre- 
judiced observer that chlorophyll undergoes an entire change 
under the influence of acids. Nevertheless we still find it 
asserted occasionally that chlorophyll remains unaltered in 
the presence of even strong acids. In a memoir published 
in 1884 Hansen affirms that pure chlorophyll is not essentially 
changed by the action of sulphuric or hydrochloric acid, and 
he is of opinion that the product obtained from impure solu- 
tions of chlorophyll by contact with acids is not a product 
of decomposition of the colouring matter, but a mixture of 
unknown substances formed by the action of acids on the 
complex alcoholic vegetable extract. In holding this opinion, 
however, the author, I think, stands almost alone. 
Considering the ease and rapidity with which, as is well 
known to all who have worked with it, chlorophyll is de- 
stroyed when its solutions are exposed to air and sunlight, 
it may appear strange that the colouring matter should not 
be completely destroyed, instead of being merely modified or 
altered by energetic agents, such as sulphuric or hydro- 
chloric acid. In fact, however, chlorophyll is not merely 
modified by the action of these acids, it is completely meta- 
morphosed, yielding products of an exceedingly stable cha- 
racter, products which remain unchanged when exposed to 
influences which would rapidly destroy the mother-substance, 
one of the most singular facts connected with the chemistry of 
chlorophyll. 
