110 TOW CRUPS GROW. 
parts of plants usually contain chlorophyll only at their surface, anu 
in quantity no greater than colored fabrics contain the particles of dye, 
Chlorophyll being soluble in ether, accompanies fat or wax when these 
are removed from green vegetable matters by this solvent. It is soluple 
in chlorhydrie and sulphuric acids, imparting to these liquids its in- 
tense gizsen color. According to Pfaundler, the (impure?) chlorophyll 
of grass kas the following percentage composition : 
Carbon 60.85 
Hydrogen 6.39 
Oxygen = 82.78 
Fremy has shown that chlorophyll may be easily decomposed into two 
coloring matters, a yellow, Zanthophyll, and a blue, Cyanophyll. This is 
accomplished by treating chlorophyll with a mixture of chlorhydric acid 
and ether; the cyanophyll dissolves in the latter, and the zanthophyli is 
taken up by the former solvent. The yellow color of autumn leaves is 
perhaps due to zanthophyll. 
According to Sachs, there exists in those parts of plants, which, though 
not green, are capable of becoming so, a colorless substance, Leucophyll, 
which, in contact with oxygen, acquires a green color, being converted 
into chlorophyll. 
Vamnim is the general designation of the bitter, astringent prin- 
ciples, (used in leather-making,) of the bark and leaves of the hemlock, 
oak, sumach, plum, pear, and many other trees, of tea, coffee, and of 
gall-nuts. It is found in small quantity in the young bean plant, and in 
many germinating seeds. 
Tannin is closely related to the carbohydrates, as is demonstrated 
alike by the microscopic study of its development in the plant, and by 
our knowledge of its chemical composition. The tannins are weak 
acids, and are distinguished, according to their origin, as Gallotannic 
acid (from nut-galls), Caffeotannic acid (from coffee), Querecitannic acid 
(from the oak), ete. As already hinted, the tannins are Glucosides, or 
compounds of sugar, with some other substance In gall-tannin the 
sugar is glucose, and the substance associated with, or rather yielded by 
it on decomposition, is known as Gallic acid. By boiling gall-tannin 
with a dilute acid, or by subjecting its solution to fermentation, decom. 
position into the two substances named is accomplished. 
According to Strecker, the composition of gall-tannin and this con- 
version are indicated by the following formule: 
Tannin. Water. Gallic acid. Glucose. 
2 (Coy Hoo Our) + 8 (Hy 9) = 6 (C, He Os) + Cio Hog Or 
Tue ALKALOIDS are a class of bodies very numerous in poisonous and 
medicinal plants, of which they usually constitute the active principle. 
Those which have an agricultural interest are Nicotin, Caffein, and 
Theobromin, 
Nicotin, C,o Hy, No, is the narcotic and extremely poisonous prin- 
ciple in tobacco, where it exists in combination with malic and citrie 
