7 a 
BULLETIN OF THE BUSSEY INSTITUTION. 287 
will be found to depend upon some peculiarity of the crop which 
promotes the growth of the nitric ferment in the soil beneath it, 
and so makes the nitrogen of the vegetable-mould available as 
plant food. 
The making of composts in particular (from earth and dung) 
may soon cease to be regarded as a subject of technical chemistry, 
and the consideration of the theory of composting may pass from 
the chemist’s hands into those of the botanist or biologist. For, 
accordingly as the ferment organism is found to be a cryptogamic 
plant or a minute animal, the process of compost-making will come 
to be looked upon either as a horticultural operation, like the cul- 
tivation of mushrooms, or a question, as one may say, of stock- 
raising. When the proper rules have been discovered, the 
compost-maker will doubtless rear the ferment organism in special 
beds and sow 'the spawn upon the compost-heap in some definite 
and methodical way; or, in many cases perhaps, he may sow the 
ferment germs directly upon the soil of the fields which are des- 
tined to bear grain or some other agricultural crop. 
I have myself recently noticed in field practice a striking in- 
stance where the spreading upon grass of loam which was presum- 
ably charged with the ferment organisms did manifestly supply the 
grass with some kind of active nitrogen. The observation was as 
follows: in building a gravel road for an avenue across the Plain- 
field, a small depression upon the surface of the land was filled up 
with loam taken from the bed of the avenue, in such manner that 
there was a thick layer of loam, perhaps two or three feet deep, 
close beside the nearly flat avenue at its lowest point, where the 
rain-water flowed from it. After the loam had lain in this position 
undisturbed for four years, covered all the while with’a thick mat 
of grass, a quantity of the loam was removed in early summer from 
in 1747, when insisting upon the importance of tilling Indian corn thoroughly 
(a process, by the way, which probably promotes nitrification), ‘‘ What is 
still more remarkable, if the Indian corn be well tilled the next crop, whether 
it be oats or flax, so much the bigger and better will that succeeding crop be, 
so that the land must have gained strength and riches; if it were not so, why 
did not the Indian corn exhaust and spend the strength of the land, especially 
when we consider how large corn is made to grow by the good tillage? But 
we find the contrary, the better the crop of Indian, the better will be the crop 
of oats.” 
Manifestly, the old French practice of taking a crop of maize before 
wheat, and that in the face of a popular tradition that wheat should follow a 
bare fallow, is pretty good evidence that a maize crop must leave behind it 
in the soil some kind of available nitrogenous food. 
