2 THE ROYAL SOCIETY OF CANADA 



These conclusions were based practically on the results obtained 

 in the winter of 1916-17, for although experiments had been carried 

 on for five years, in no single year had it been possible to obtain 

 sufficient data. For the winter of 1917-18 a very complete series of 

 tests was planned to cover all doubtful points and in order to keep a 

 close check on the bacterial content of the different soils fortnightly 

 analyses were taken. 



In this part of Quebec the soil seldom freezes until January, and 

 as the bacterial content of the soil is very low in November all soil 

 testing was started in this month. Unluckily the winter of 1917-18 

 was most unusual. Severe frost set in before the end of November, 

 whilst there was practically no snow covering. In the first week of 

 December the ground was frozen to much greater depth than during 

 any winter since soil analyses were undertaken in 1912. This early 

 severe frost was followed by very unsettled weather during February 

 and March, interfering with the taking of the soil samples. The soil 

 conditions do not represent the ones usually found in Eastern Canada, 

 but give a good indication of what happens in soils in winter in the 

 prairie provinces, where there is severe frost and only a light snow 

 covering. 



The soils investigated were the same as those used the previous 

 year : — 



1. Quantitative and qualitative determination of bacteria in the 

 soil from a cultivated field. The soil consisted of a light rich loam 

 to a depth of eighteen inches and was free from stones. Onions were 

 grown on this field, which was subsequently manured and ploughed. 



2. Quantitative and qualitative determination of bacteria in the 

 soil of a plot which had been fallowed for four years. The soil consisted 

 of a clay loam nineteen inches deep, resting on bed rock but well 

 drained. 



3. Quantitative and qualitative determination of bacteria in the 

 same soil as described in Experiment 2, but this plot was sown to 

 grass for three years. 



4. Quantitative and qualitative determination of bacteria from 

 soil beneath a lawn. The sod was eight years old and the soil was 

 very poor and gravelly. This plot was kept free from snow until 

 February, when a continued heavy snowfall prevented any snow 

 removal. On Febraury 20th a heavy rainfall flooded this field and 

 further sampling was impossible until April. This was the field 

 mentioned in Experiment 2 the year before. 



5. Quantitative and qualitative determination of bacteria in 

 cultivated black muck soil. This field was flooded in the end of 



