110 
merited or unfermented, are comparatively of little value to 
the growing plant. 
II. The opinions of Liebig, concerning the origin and 
assimulation of nitrogen^ are of great value in an agricultural 
point of view. He establishes the fact that this organic 
element is uniformly derived from ammonia. He has demon- 
strated the existence of ammonia in rain-water to the amount 
of one quarter of a grain to the pound, by original experi- 
ments. Nitrogen, which has hitherto been thought only to 
be contained in those plants which contain gluten, he has 
found in all plants examined. Ammonia," says he, "exists 
in every part of plants, in the roots, in the stem, and in all 
blossoms. It yields nitrogen to the vegetable albumen, the 
principal constituent of ^plants. Nitrogen exists in corn, 
grass, and all plants without exception. We may furnish a 
plant with carbonic acid and all the material which it may 
require ; we may supply it with humus or decaying vegetable 
fibre in the most abundant quantity, but it will not attain 
complete development unless nitrogen is afibrded it — a herb 
will be formed, but no grain ; sugar and starch may be pro- 
duced, but no gluten." But the formation in plants of sub- 
stances containing nitrogen, such as gluten, takes place in 
proportion to the quantity of this element which is conveyed 
to their roots in the state of ammonia derived from the putre- 
faction of animal matter. 
Thus Pronst found per cent. 
French Wheat to contain 12.5 gluten. 
Bavarian, ditto 24.0 
Winter, ditto 19.0 „ 
Summer, ditto 24.0 „ 
Sicilian, ditto 21.0 „ 
Barbary, ditto 19.0 „ 
Alsace, ditto 17.3 „ 
Jardin des Plantes, ditto 26.7 „ 
Winter Wheat in ditto o 3.33 „ 
