SECTION VI 



RELATION OF MICROORGANISMS TO THE PHYSICAL 

 PROPERTIES OF SOIL 



Exercise i 



Movemeats of Soil Water 



1. Prepare four glass cylinders or large test-tubes as 

 follows: Fill two three-fourths full of quartz sand and 

 two three-fourths full of soil. 



2. Treat as follows: 



(a) Sand plus i per cent of sugar bouillon previously inoculated with 



5 c c. of a rich soil suspension 



(b) Sand plus i per cent of sugar bouillon previously inoculated with 



5 c c. of a rich soil suspension 



(c) Soil plus I per cent sugar 



(d) Soil plus I per cent, sugar. 



3. Add enough bouillon to the sand and enough water to 

 the soil to completely saturate the columns. 



4. In order to prevent bacterial growth add 5 c.c. of 

 a I : 5 mercuric chlorid solution to cylinders {a) and (c), 

 and the same amount of water to cylinders (b) and (d). 



5. Mark on the cylinders the height of the column of 

 water. 



6. Incubate at 28° C, and examine each day. 



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