292 PROCEEDINGS OF THE INDIANA ACADEMY OF SCIENCE. 



present in the 1-400 bacterial dilutions. 10 cc aliquots would cause .092 anu 

 .094 grams of soil respectively, to be present in the 1-400 bacterial dilutions. 

 The variation in these figiu-es is not 1.5 to 1.0 nor 1 to .8 and thus would not 

 account for the variation in the ammonium hydroxide tests on the bacterial 

 dilutions made from soils No. 1, and No. 2. As a result of these two tests it 

 is thought that 1 cc is too small an aliquot of a water and soil mixture to be 

 taken as representative. 



To determine whether there is more uniformity between triplicate ten 

 cc aliquots from the same bottle than there is between triplicate one cc 

 aliquots from the same bottle, the following experiment was undertaken. 

 All aUquots were taken from the 1-4 bacterial dilutions of the soils used. 

 The acid peat and the acid black sand used were the same soils used in a prev- 

 ious test except that they were oven dried and reground in a mill. The red 

 silty clay is a "freak" soil, so fine that it dusts, and contains a large percentage 

 of soluble matter. The one cc aliquots were taken first and then the ten 

 cc aliquots were taken from the same bottle. The mixture of soil and water 

 was always in motion when aliquots were drawn. 



Table II. 



Uniformity of 10 cc and 1 cc aliquots of 1-4 bacterial dilutions of tlwep 

 soils. 



The table shows : 



1. That the differences between the results obtained with tri])licate 1 cc 

 aliquots and triplicate 10 ec aliquots vary as the type of soil. 



2. That the soil in the soil and water mixtures is not accurately aliquoted. 



3. That variation between one cc aliquots is so great that the increasing 

 concentration of the soil in tlie mixture (due to 2) does not regularly increase 

 the amount of soil in each succeeding aliquot. 



