FLORIDA STATE HORTICULTURAL SOCIETY. 
This is a most difficult question to an¬ 
swer, and at present can only be answ^^r- 
ed in part by Science. It is along this line 
that bacteriology together with chemistry 
and physics have accomplished great 
work in recent years. 
Bacteriology, the youngest of all the 
sciences has shed the greatest amount of 
light upon this question. During the last 
two decades this science through its many 
researches tells us of a great number of 
micro-organisms that have the power of 
fixing nitrogen; that is, they are capable 
through unknown processes to cause ele¬ 
mentary nitrogen to combine with cer¬ 
tain other elements present to form com¬ 
pounds of Nitrogen which are available 
as food for higher plants. 
These nitrogen fixing micro-organisms 
may be divided into two classes, symbio¬ 
tic and non-symbiotic. 
The greater amount of research has 
been devoted to the former, and therefore 
they are best known *at present. 
These symbiotic micro-organisms are 
always found intimately associated with 
certain higher plants especially the papil- 
lionaccae or leguminosae (beans, peas, 
clover, etc.) in whose roots they reside. 
The amount of nitrogen that may be fix¬ 
ed by these micro-organisms is large and 
the cultivation of legumes should always 
be encouraged. 
Of late years our National Department 
of Agriculture has been making great ef¬ 
forts to devise a reliable method by means 
-of which the micro-organisms above men¬ 
tioned may be readily distributed in a 
commercial way. 
The method of drying the cultures on 
cotton, recommended so highly not longer 
than a couple of years ago, has recently 
been shown to be but at best partially suc¬ 
89 
cessful. Still a reliable method will un¬ 
doubtedly be forthcoming before long. 
To the second class or non-symbiotic 
nitrogen fixing micro-organisms belong 
those of bacteria that have the power of 
fixing elementary atmospheric nitrogen 
unaided by any host. These organisms 
have not as yet been studied extensively, 
still a large number of forms have been 
discovered. 
Besides the nitrogen fixing bacteria 
just discovered, there are forms of micro¬ 
organisms that have an opposite function, 
that is, they have the power of breaking 
up nitrogenous compounds with the lib¬ 
eration jof elementary nitrogen. There¬ 
fore the action of these bacteria result in 
the loss of fixed nitrogen in the soil. 
These organisms can, however, be readily 
controlled by the prop>er drainage and cul¬ 
tivation of the soil, for they are as a rule 
anarobic, (not capable of existing in the 
presence of air) or at best but slightly 
facultative (capable of existing in or not 
in the presence of air.) 
Another natural agency by means of 
which atmospheric elementary nitrogen 
is fixed is through electrical discharges. 
For many years it has been known that 
lightning discharges cause atmospheric 
nitrogen to combine with oxygen to 
from oxides: These in turn unite with 
aqueous vapour to form nitric and ni¬ 
trous acids, which are washed out of the 
air into the soil by the rain. 
It must be borne in mind that but a very 
limited amount of atmospheric nitrogen 
is fixed in this way. 
As far back as 180 years ago Caven¬ 
dish, one of the founders of modern chem¬ 
istry, predicted the commercial fixation of 
atmospheric nitrogen and a few years la¬ 
ter contemporaneously with Priestly 
