SUGGESTION S CONCERNING THE TERMINOLOGY OF 
SOIL BACTERIA 
Jacos G. LipMAN 
The period 1890-1910 has been one of notable progress in soil 
bacteriology. It is marked, on the one hand, by the appearance 
of Kramer’s book' and, on the other, by the publication of LOHNIS’ 
handbook? A comparison of these two works will show not only 
a rapid increase in the body of facts relating to soil bacteria, but 
also a series of more or less successful attempts to arrange these 
facts in an orderly fashion. There have been created in this man- 
ner a number of terms that are to designate certain groups of 
physiological functions or reactions, like nitrogen-fixation, nitri- 
fication, denitrification, sulphate-reduction, etc. 
As we inquire into the meaning of the different terms thus 
created, we find much that is indefinite and confused. We find, like- 
wise, that other terms, while definite enough as to their meaning, are 
too unwieldy for use in the lecture room. For instance, the term 
“denitrification,” already well established in our terminology, 1S 
not at all definite. The earlier investigators employed it to 
designate the reduction of nitrates,} irrespective of the fact whether 
the reduction products were nitrites, ammonia, nitrous oxide, 
or nitrogen gas. Latterly there has been a tendency to restrict 
the use of the term to the complete reduction of nitrates, involving 
the liberation of nitrogen gas, or at most of nitrous and nitric 
oxides. Kayser‘ and after him Loxnis’ have attempted to dis- 
tinguish between complete and partial reduction of nitrates by 
employing the terms ‘‘direct denitrification’ and ‘‘indirect denitri- 
* Die Bakteriologie in ihren Beziehungen zur Landwirtschaft. Vol. 1- Wien. 
. + Handbuth der landwirtschaftlichen Bakteriologie. Berlin. 1919. 
3 Gayon and Dupetir, Recherches sur la ee | des nitrates par les infiniment 
petits. Station Agronomique de Bordeaux. Nancy. 1886. 
4 Microbiologie Agricole, p. 117. 
5 Handbuch der landwirtschaftlichen Bakteriologie, p. 447- 
Botanical Gazette, vol. 51} Me 
