| among its particles. 
304 
skill as to the known or ascertained consti- | merely serve as the germ and the delineator of 
tuent elements. “Cattle and horses were fed 
upon weighed quantities of different kinds of 
food, and the effect produced upon them accu- 
rately observed, both as regarded increase of 
weight, health, and vigour ; and as the results of 
these experiments, a table of the relative nutri- 
tive powers of different articles of food was drawn 
up, each article having an equivalent assigned to 
it,—100 lbs. of meadow hay being taken as the 
standard of comparison. From a careful perusal 
of these tables, M. Boussingault was led to the 
conclusion, that the difference in the value of the 
various articles of food corresponded with the 
difference in the proportion of their azote. He 
therefore analyzed with great accuracy a consi- 
derable number of vegetables, and arranged them 
in a table, in which the equivalents assigned to 
each plant designated the exact quantity of azote 
which it contained as compared to 100 lbs. of 
| meadow hay, the equivalent, of course, increasing 
as the proportion of azote diminished. Now, on 
comparing these two tables, the most astonish- 
ing concordance is observed; indeed, when it is 
considered that M. Boussingault’s results must, 
of necessity, be absolute, whereas the practical 
equivalents may be rendered uncertain by many 
fortuitous circumstances, as the health of the 
| particular animal employed, &c., the coincidences 
which occur are truly surprising. For example, 
concerning one of the least. nutritious kinds of 
food, the turnip, M. Boussingault considers 612 
as its equivalent, and M. Thaér, who examined 
it practically, fixes it at 611. This table, which 
is full of interest, is published in the 63d volume 
of the ‘ Annales de Chimie et de Physique.’ Surely 
such experiments as these must prove to demon- 
stration that, ceterts paribus, that food is most 
nutritious which contains the greatest quantity 
| of azote, and, vice versa, that a deficiency of azote 
in any article of food will indicate a correspond- 
ing deficiency in its power of supplying nourish- 
ment.” [Dr. Madden in Quarterly Journal of 
Agriculture. | 
Every plant, during its life, fixes azote; and 
appears to obtain some of it from the atmosphere, 
most of it from manures, and probably all of it 
in the form of ammonia and nitricacid. All the 
organs of a plant, without exception, commence 
their formation with a nitrogenous matter analo- 
gous to fibrin; and they ever afterwards have 
this matter in association, not only with the amy- 
laceous secretions, but even with the cellular and 
the ligneous tissues, The nitrogen fixed by every 
nascent or rudimental plant produces a concrete 
fibrinous substance, which constitutes the rudi- 
ment of all the vegetable organs; and this sub- 
stance is never afterwards destroyed, but is al- 
ways to be found, no matter in how minute an 
aggregate quantity, or how excessively or almost 
atomically divided by the interposition of enor- 
mous proportions of non-nitrogenous matter 
Nor does this substance 
the several organs ; but it also produces the 
liquid albumen which the coaguble juices con- 
tain, and the caseum which is so often con- 
founded with albumen, but whose separate exist- 
ence in many plants can be easily recognised. 
The fibrin, the albumen, and the caseum of plants 
are their grand nitrogenous elements; they have 
a closely similar composition to one another ; and 
they present a striking parallel or counterpart to 
respectively the ligneous matter, the amidine 
and the dextrine. For fibrin, like the ligneous 
matter, is insoluble,—albumen, like amidine or 
starch, coagulates by heat,—and caseum, like 
dextrine, is soluble; these nitrogenous elements, 
as well as the three parallel non-nitrogenous ele- 
ments, are neutral; and they act the same part 
by their abundance in the animal kingdom, which 
the ligneous matter, the amidine, and the dex- | 
trine, act by their abundance in the vegetable 
kingdom. “ Besides,” says M. Dumas, “in like 
manner as it suffices for the formation of non- 
azotated neutral matters, to unite carbon with 
water or with its elements, so, also, for the for- 
mation of these azotated neutral matters, fibrin, 
albumen, and caseum, it suffices to unite car- 
bon and ammonium with the elements of water ; 
forty-eight molecules of carbon, six of ammo- 
nium, and seventeen of water, constitute, or may 
constitute, fibrin, albumen, and caseum. Thus, 
in both cases, reduced bodies, carbon or ammo- 
nium and water, suffice for the formation of these 
matters; and their production enters quite na- 
turally into the circle of reactions, which vege- 
table nature seems especially adapted to pro- | 
duce.” The great facts, then, that fibrin, which 
serves as the rudiment of all the organs of plants, 
is a nitrogenous element,—that albumen and 
caseum, which are so largely diffused in all the 
most nutritious plants, and which are assimilated 
or modified by animals according to the exigen- 
cies of their nature, are nitrogenous elements,— 
that these three chief proximate elements of bulk 
in animals, which correspond to the three chief 
proximate elements of bulk in vegetables, are 
nitrogenous elements,—these facts powerfully 
evince that the function of nitrogen in plants, 
and the part which it plays in the reciprocities 
of elements upon a farm, are worthy of very seri- 
ous study. 
A considerable part of the azote fixed by 
plants appears to be obtained, if not from atmo- 
spheric air, at least from gaseous matter held in 
mechanical mixture with the atmosphere. 
Boussingault instituted experiments, to ascer- 
tain whether developed plants, endowed with 
perfect organization, obtain azote, when they 
are cultivated in a soil absolutely deprived of 
organic matter; and he found that clover grown 
in sand, which had previously been calcined to a 
red heat, receives into its organization a certain 
quantity of azote, and that pease grown under a 
M. | 
similar regimen, and having for their whole food | 
