Nov. 
THE CULTIVATOR. 
too great activity, another must fall below the normal 
standard. If the organs of vegetation , i. e. the stem, 
branches and leaves,- manifest a luxuriance' of growth 
beyond a certain measure, it happens at the cost of 
the organs of reproduction. The flowers are barren j? 
the plant bears no fruit. 
In my experiments, certain plants which had grown 
until flowering-time, were at that period brought into 1 
an ammoniacal atmosphere. The ammonia caused 
them to put forth a certain number of new leaves, the 
formation of which destroyed the equilibrium net ween 
the vegetative and reproductive functions, so that the 
former predominated. 
V. The influence of ammonia is unequally active in 
different periods of vegetable growth. Its. effects are 
more evident between germination and flowering, than 
from the latter to the ripening of the fruit. This dif¬ 
ference is easily understood. 
Until the time of blossoming, the whole activity of 
the plant expends itself in the foliage. Under favora¬ 
ble influences are formed a large number of leaves, 
which, as organs of absorption, unite their action with 
the cause that led to their production ; they owe their 
development to the action of the older leaves, and lend 
their offices to the formation of new ones. 
From the blossoming forth, on the contrary, the en¬ 
tire energies of the plant are expended upon the re¬ 
productive organs. A part of the leaves wither and 
fall off. Those which still grow, do not nearly attain 
the size of the older ones. Consequently the surface of 
absorption has diminished, and ammonia can no longer 
be taken up by the plant to the same extent as before. 
On the other hand, after flowering, the plant approach¬ 
es the limits of its growth. These two considerations 
explain the fact that the influence of ammonia is de¬ 
cidedly less in the second stage of growth than in the 
first. 
VI. Ammonia in the gaseous form, will unmistakea 
bly find application in hot-houses. The results of my 
experiments are so striking, that the question of its 
practicability may be considered as definitely settled. 
I have produced extraordinay luxuriance of vegeta¬ 
tion in a hot-house containing orchidaceous plants, by 
adding to the air 2-10.000 of its weight of ammonia— 
i. e. one-half the quantity employed in the above ex¬ 
periments. 
VII. During the dry heats of summer, ammonia is 
apt to act injuriously. It is therefore well to discon¬ 
tinue its use in the months of June, July and August. 
The bad effects which I have observed, have always 
arisen under the same circumstances, and with cha¬ 
racters so constant, as to indicate a well defined phe¬ 
nomenon. They are especially noticeable in plants 
whose vegetation is considers bly advanced. The leaves 
become yellow, contract, and dry up; notwithstanding 
the atmosphere is saturated with moisture. The evil 
spreads ever nearly the whole plant, excepting a cer¬ 
tain number of the uppermost leaves, and the plant 
dies. The cause of this appearance is a wrong relation 
between the quantity of nutritive material absorbed by 
the leaves, and that taken up by the roots. 
In general, the root's are especially destined-to pro¬ 
vide - the'plant with mineral matters. When the ab¬ 
sorption of these passes certain’ limits, the plant is 
unable to appropriate them; and- they are deposited in 
white, salt-like erusts on the surfaces of the leaves. 
This may often be observed o» the broad leaves ©f the 
melon tribe, when dry weather succeeds a strong rain. 
When by the co-operation of various efreumstan- 
ces, the activity of the leaves exceeds that of the roots, 
the absorption of organic matter predominates. From 
want of a sufficient quantity of inorganic (mineral) 
matters, the organic elements eannot be disposed of- in 
the natural manner. A remarkable phenomenon now 
appears. What the roots of the plant are not able to 
furnish, for the development of the younger growing 
organs, the plant seeks to provide from its own struc¬ 
ture j there occurs a reabsorption of inorganic matter, 
from a certain number of old leaves, which according¬ 
ly wither and perish. The disturbance that the vege¬ 
table organism suffers in this way, is so 1 great that in 
time the whole plant dies. 
In nature, frequent examples of this kind occur. 
If a Portulaeca stem in flower, is cut from the parent 
plant, and laid on a sheet of paper in the shade, the 
growth continues, the seeds are formed and even ripen. 
In this ease the inorganic substances of the seed cannot 
come from the soil ; they must he derived from the 
tissues of the plant itself. Quite similar is the ease I 
have mentioned above. 
VIII. To recapitulate : 
1. 4-10 000 of ammonia, added to the atmosphere, 
decidedly favors vegetable growth. 
2. Harvests, yielded by plants grown in such an at¬ 
mosphere, contain much more nitrogen than an equal 
harvest produced in pure air. 
3. If the use of ammonia is begun two or three 
months before the time of flowering, the vegetation 
follows its usual course of development, and there re¬ 
sults no disturbance of the succession in which the 
various organs of the plant are unfolded. 
4. If the application be commenced just as the plant 
is about to put forth flowers, the blossoming is partially 
or entirely checked. The plant produces numerous 
new leaves, but no fruit. 
NOTE BY THE TRANSLATOR. 
The autbc#promises a detailed account of his appli¬ 
cation of ammonia in green-houses, but no notice of 
it has yet met my eye. There appears to be no doubt 
that it may thus be employed, whether with greater 
advantage thiough the air than through the soil, is 
perhaps not fully settled. An arrangement to charge 
the air of a green-house with ammonia, to a suitable 
extent, might be constructed without great expense, 
and would probably be very advantageous in forcing 
succulent vegetables like asparagus, which flourish un¬ 
der very heavy manuring. 
Whatever may prove to be the direct practical value 
of this discovery, it is certain that the remarkable re¬ 
sults obtained will attract attention to this subject, and 
we may hope before long to possess more definite know¬ 
ledge concerning the action of manures. 
