846 
The Micro-orrfmmms of the Soil. 
Pasteur’s theory is that “the chemical act of fermentation is 
essentially a correlative phenomenon of a vital act beginning and end- 
ing with it ; there is never an alcoholic fermentation without there 
being at the same time organisation, development, multiplication 
of globules, or the continued consecutive life of globules already 
formed.” 
Examples might be cited to show that the slightest changes in 
nutrients may render them worthless, as such, to certain ferments, and 
available to others. 
The Micko-organisms of the Soil. 
Tliese organisms may, according to their actions, be divided into 
three groups : — (1) those which oxidise constituents of the soil, (2) 
those which reduce or destroy the same, and (3) those by whose 
activity the soil is enriched. As regards the first group, the oxidation 
can take place in two ways — they can either oxidise by assimilating 
the organic substances of the soil and reducing them to carbonic 
acid and water, in order to obtain the necessary heat and energy ; 
or they can oxidise by giving off oxygen. The first may be termed 
intra-cellular, and the second extra cellular acting organisms. 
Intra-cellular Action . — Amongst the intra-cellular we have, pri- 
marily,The usual ferments of decay, which assimilate and respire at the 
expense of the carbon compounds. In some cases the organisms have 
accommodated themselves to seemingly most remarkable materials 
for respiration, the combustion of which aflFords the necessary heat. 
Thus the Iron Bacteria of Winogradsky require ferrous carbonate 
for their life and development, oxidising the same to oxide. This 
can be physiologically interpreted as a respiration process, the 
protoxide of the re.spiration material becoming the oxide of respira- 
tion product. 
The Sulphur Bacteria are equally remarkable. Their cells are 
distinguishable by containing from time to time granules of amor- 
phous sulphur. These organisms were formerly regarded as causing 
the formation of sulphuretted hydrogen in sulphur springs. 
Winogradsky claims the reverse to be the case. They do not 
produce sulphuretted hydrogen but consume it, burning it partially 
first to sulphur (which deposits in the cell) and water, then completely 
to sulphuric acid, which passes out and forms sulphates from the 
carbonates of the surrounding water. When no more carbonates 
are present, the combustion of sulphur to sulphuric acid ceases. 
Physiologically this is also a process of respiration directed towards 
generating heat and energy ; sulphuretted hydrogen is the respira- 
tion material and sulphuric acid the respiration product. 
Ceitain nitrification ferments can be regarded as intra-cellular. 
They may take up ammonia and give it ofi‘ as nitrates, this process 
ceasing, as in the case of the Sulphur Bacteria, when no more 
carbonates are present. 
We now come to the discussion of two ferments, the concomitant 
actions of which have heretofore caused much confusion. Schloesing 
