96 Schunck . — The Chemistry of Chlorophyll, 
action of citric, malic, or phosphoric acid. To each sub-group 
belongs a distinct spectrum. The ferrous compounds are 
changed by the action of hydrochloric acid, but without yield- 
ing phyllocyanin as a product of decomposition as do the 
zinc compounds, occupying In this respect, as in most others, 
a position intermediate between the cupric and zincic groups. 
That silver should yield a compound with phyllocyanin and 
acetic acid, and lead should not, is a singular fact, proving, as 
do other facts that I have mentioned, that phyllocyanin is a 
substance possessing very peculiar properties. 
I have entered into a more detailed description of these 
compounds of phyllocyanin than would seem to be required 
on this occasion, because in my opinion chlorophyll itself be- 
longs, for reasons which I shall state presently, to the same 
class of compounds, though it is not identical with any one and 
indeed differs widely from most of them. 
Reducing agents act in a peculiar manner on phyllocyanin, 
giving rise to products which cannot be reconverted Into 
phyllocyanin by oxidation, and are therefore not so-called 
leuco-bodies like indigo-white. When metallic tin Is added 
to a solution of phyllocyanin in concentrated hydrochloric 
acid, the solution on standing gradually loses its bright bluish- 
green colour and becomes of a dull olive-green. The solution 
now gives with water a brown precipitate, which filtered off 
and washed is almost entirely soluble in ether. The ethereal 
solution has a green colour with a tinge of red, and shows a 
spectrum consisting of eight bands ; it leaves on evaporation 
a semi-crystalline residue, which is green by transmitted, 
purple by reflected light. By the prolonged action of tin on 
a solution of phyllocyanin in hydrochloric acid a further and 
more complete change is effected, the solution acquiring a 
bright red colour without the least tinge of green 1 . On the 
addition of water the solution gives a red flocculent precipitate, 
which filtered off and washed dissolves in alcohol with a bright 
1 Berzelius observed a similar reaction on treating chlorophyll dissolved in 
hydrochloric acid with metallic zinc. 
