THE INFLUENCE OF Low TEMPERATURE ON Sort BActeriIA 1057 
There was an increase of about 50 per cent in the bacteria count 
when the soil was thawed by adding water at 30° C., over the count from 
the sample allowed to thaw in the air. This would seem to indicate 
a breaking up of the clusters of bacteria, due to the sudden change in 
temperature. 
EFFECT OF ALTERNATE FREEZING AND THAWING ON BACTERIA 
COUNT 
If there is a breaking up of the masses of bacteria when subjected 
to extreme temperatures, then alternate freezing and thawing should have 
some effect. In the test to determine this point the soil was placed in two 
containers 10 by 6 by 4 inches in size and divided into compartments by 
means of strips of paper. One of the containers was brought in each day 
and allowed to thaw at room temperature, counts were made of the bacteria 
per gram of soil in one of the compartments, and the container was then 
placed outside to freeze again. The outer container remained frozen during 
the experiment. The results are shown in table 3: 
TABLE 3. Errect or ALTERNATE FREEZING AND THAWING ON THE BAcTEnIA CoUNT 
Bacteria 
Day Treatment per gram of 
dry soil 
TENE Soca oso nae INOS a 0 [ere een ee Ba eatin Cnet A eee incl Wiss aa 4,500,000 
SBCOIG) oS mare Soles ee rozenvandetha wed tapas sae aya eiaht ea a ae 7,000 ,000 
pind hese. nike se: Hrozenyandsthawed erry as see na eae waar 8,100,000 
ounthperse ane oc ce: Ityoyzsin ENV! WOOO ob oscoosoeoeooscoabeéunoodaas 10, 200 ,000 
JET Oa 5 Spices coerce nrozentandgonawe Garis ree amir paren go eee auE 11, 200 ,000 
SUL os ha g RO GeO Ree roan Gone! Wal ocodcoceoopaundcdednovodoauace 11,100,000 
Deverltbeeeicnnec. 3. hrozenvand: thawed temenrst sss atrpar. jen ce ihre 11,900,000 
IBIAS oe.ocie-ae eee Continually frozen....... EH Nakd i WaT Rea ons Pee eel 8,900 ,000 
The results shown in table 3 would seem to indicate that alternate 
freezing and thawing did have some effect, until the fifth day at least. 
After that there was little or no increase. There is one thing that must 
be taken into consideration in all these results, and that is the possibility 
that some of the bacteria may be killed by freezing and that the number 
as shown by the plate count may represent a greater breaking-up of the 
masses than the results would otherwise indicate. Inasmuch as the pots 
were only 4 inches deep, and the samples from which the counts were made 
