Dormant and Active Ingredients of the Soil. 
241 
From these facts, and from others stated in the course of my 
memoir, I have conceived myself warranted in deducing the fol- 
lowing conclusions : — 
1st. That'll is quite consistent with the general tenor of the 
preceding facts and observations, to maintnin with Boussingault, 
that the falling off of a crop is dependent as well upon a deficiency 
of organic matter proper to promote the nutrition of the plants, 
as upon a failure of its inorganic principles ; not indeed that 
the organic matter enters, as such, into the constitution of the 
vegetable, but that by its decomposition it furnishes it with a 
more abundant supply of carbonic acid and ammonia, which 
supply accelerates the development of its parts, and thus at once 
enables it to extract more inorganic matter from the soil, and en- 
ables the soil to supply it more copiously with the principles it 
required for its nutrition. 
Hence, perhaps, in part, the advantage of intercalating the 
Leguminosa? and other fallow crops, which generate a larger 
amount of organic matter than the Cerealia, and which thus serve 
to enrich the soil by what they leave behind them. 
2ndly. That it by no means follows, because a soil is benefited 
by manuring, even though that manure may, as in the case of 
bones, guano, &c., derive its efficacy from the phosphates it 
supplies, that it is therefore destitute of the ingredient in ques- 
tion, since it may happen that it possesses abundance of it in a 
dormant, though not in an immediately available, condition. 
In these cases, in which the agriculturist has been assured by 
the results of actual analysis, that there is no real dearth of the 
principles essential to his crops in the soil under cultivation, but 
where he has ascertained, either by the chemical mode pointed 
out, or by an experience of the good effects brought about by 
manures, that the substances in questiim are not in a state to 
become immediately applicable to the purposes of vegetation, 
three courses appear to be open to him : — 
1 St. To apply a sufficient quantity of the same materials in a 
state in which they can be absorbed by the plants without delay; 
2ndly, to allow the ground to remain fallow, by which expedient 
time is given for a further decomposition of its materials, and 
for a renewed extrication of its useful ingredients, to take place; 
3rdly, to produce, by the various methods in daily use, such a 
stirring and pulverization of the ground, as may admit of a more 
thorough admission of air and moisture, and consequently acce- 
lerate the process of disintegration in a greater degree than would 
take place under natural circumstances. 
Examples will occur to every one of the successful adoption of 
each of these three practices : of the first, in the ordinary process 
of manuring, and especially in the beneficial consequences result- 
VOL. VII. u 
