434 
PHYSIOLOGY. 
BOOK IT. 
according to Berzelius [Comptes rendus^ vi. 644.), so economi- 
cally distributed, that he is persuaded that there is not oz. 
(10 grammes) of it in all the leaves of a large tree. This 
great chemist states that it is infusible at 200°, when it begins 
to decompose ; insoluble in water, moderately soluble in 
alcohol and ether. It is dissolved in concentrated sulphuric 
acid and in muriatic acid equally concentrated; water then 
precipitates it. The muriatic acid may be evaporated without 
destroying the chlorophyll. It gives definite combinations 
with bases, stains aluminated wool, shows evident signs of 
reduction and reoxidation, and is also very alterable by air and 
light. 
It seems that all the other colours in plants are produced 
by alterations of chlorophyll. Macquart, while he entirely 
denies the existence of one series of oxidised yellowy-red 
colours, and of another of disoxidised cyanic colours, asserts 
that the chlorophyll yields a blue colouring matter by abstrac- 
tion of water, and a yellow colour by the addition of w^ater. 
The blue matter, or antliocyane, is an extractive matter soluble 
in water but not in alcohol ; is stained red by acids, and green 
by alkalies ; it forms the basis of all blue, violet, red, brown, 
and many orange flow'ers ; it is also found in all orange, violet, 
or blue leaves, and sometimes in roots that are not perennial. 
The yellow matter, or anthoxmithine, is an extractive resinous 
substance, partly soluble in water and partly in alcohol or 
ether, and it becomes blue by the action of sulphuric acid. 
These two colouring matters may be found in the same petal, 
but then they are contained in different cells, the anthoxan- 
thine occurring in the lower cells, the anthocyane, on the 
contrary in the more superficial cells ; and this produces a great 
variety in the colour of petals. The various hues of leaves are 
caused by the different states in wdiich chlorophyll is found, 
and also by the presence of anthoxanthine, which Berzelius 
calls xantliopliyll. Berzelius once thought that the latter was 
produced by chlorophyll under the influence of light, and that 
leaves become yellow when the secretion of chlorophyll ceases; 
but he abandoned that opinion upon finding that, when 
chlorophyll is exposed to sunlight until it becomes yellow, it 
is not xanthophyll. 
