FEBRUARY 9, 1912] 
Ca. 10 per cent. non-spore-producing, non-lique- 
fiers; short rods, immotile or with polar flagella. 
Trace. Micrococci, like the last group physio- 
logically. 
15-45 per cent. Actinomycetes. 
Of these six groups all are strict aerobes except 
a few in group 1; almost without exception none 
produce gas from sugars; while acid production, 
although common, is always very weak. 
Each group comprises about seven or eight 
types, except the last two, in which there are but 
one or two types. 
This year forty more cultures have been iso- 
lated from four other soils elsewhere in the state. 
Two were clays, one a silt and the other a sand. 
With few exceptions these cultures seem to be the 
same kinds as those previously studied, although 
the relative frequency of the types is different. 
This suggests that there is a characteristic bac- 
terial flora of soil. Accordingly, an intelligent 
comparison of soils demands the development of a 
technique to determine the relative abundance of 
the various kinds of organisms. 
Soil Organisms which Destroy Cellulose: Karu F. 
KELLERMAN and I. G. McBrrH. 
Our knowledge of cellulose destruction in soils 
is inadequate. Omeliansky’s conclusions that cel- 
lulose is destroyed only under anaerobic conditions 
and gives rise either to hydrogen or methane are 
erroneous. 
Two species of cellulose-destroying and five spe- 
cies of contaminating bacteria were isolated from 
Omeliansky’s hydrogen culture, and one cellulose- 
destroying and two contaminating forms from his 
methane culture; none of the three species showed 
any resemblance to Omeliansky’s hydrogen or 
methane ferments. In addition to the species iso- 
lated from Omeliansky’s cultures eleven other spe- 
cies have been isolated from various other sources, 
one of which belongs to the thermophile group. 
Contrary to Omeliansky’s observation that cel- 
lulose-destroying bacteria do not grow upon solid 
media, most of the species isolated were found to 
grow readily upon such media as beef agar, gela- 
tin, starch, potato and dextrose. Some of them 
have the power to liquefy gelatin. Although sey- 
eral of these organisms were isolated under an- 
aerobic conditions, they grow equally well or better 
in the presence of air, which shows that the 
destruction of cellulose by bacteria is an aerobic 
rather than an anaerobic process. 
It is usually supposed that filamentous fungi 
SCIENCE 
227 
are of little importance in agricultural soils; these 
investigations show them to be at least as impor- 
tant as bacteria in destroying cellulose. About 
seventy-five species of molds have been isolated 
representing a large number of genera; species of 
Penicillium, Aspergillus and Fusariwm are perhaps 
most numerous. 
In the destruction of pure cellulose either by 
bacteria or molds in synthetic media the asso- 
ciative action of organisms which presumably have 
no cellulose-dissolying enzymes frequently stimu- 
lates the growth of the cellulose organism and 
increases its destructive power. 
Nitrates in Soils: F. L. STEVENS. 
Nearly all text-books assert that nitrates are the 
chief source of nitrogen supply for green plants. 
Recent experiments throw doubt on this assertion. 
Attention was called to the need of tests bac- 
terially and chemically controlled, conducted under. 
natural conditions, to determine what forms of 
nitrogen are most readily available to the leading 
crop plants. Nitrification and denitrification were 
discussed. In particular question was raised as to 
the influence of organic matter mixed with nitrates 
in fertilizers (a common practise) upon loss by 
denitrification. Stress was laid upon the need of 
conducting tests in soils, not in solutions. 
Why do some Soils Nitrify Organic Nitrogenous 
Substances and the Ammonium Salts of Organic 
Acids Faster than they do Ammonium Sulphate 
or Ammoniwm Chloride? J. C. TEMPLE. 
Of 26 Georgia soils tested for nitrification, 24 
were found to nitrify tankage more readily than 
ammonium sulphate, in some cases the amount of 
nitrate recovered from tankage was ten times that 
recovered when ammonium sulphate was the source 
of nitrogen. Tankage, cotton-seed meal, cowpea 
vines, gelatin, peptone, asparagin, urea, ammonium 
citrate, ammonium oxalate, ammonium tartrate, 
ammonium bicarbonate and ammonium hydrate 
were nitrified faster than ammonium sulphate or 
chloride. This condition was not due to the nature 
of the nitrifying organism in the soil, as the same 
thing held true when the nitrifying organisms were 
supplied as pure cultures, obtained from a number 
of sources. When calcium carbonate was added to 
the soil, ammonium sulphate was nitrified as well 
as any of the other substances. 
The explanation offered for this condition was 
that these soils (all of the Cecil group) were acid, 
and that the soil organisms decomposed the sub- 
stances of organic origin in a way that more 
ammonia than acid was produced, thus correcting | 
