As has long been realised by soil bacteriologists, the present plating technique used in estimating bacterial numbers in soil suffers from the lack of a really efficient means of disintegrating the soil, so as to produce an even suspension of the organisms in the diluting fluid. As a consequence of this, although we are able, by careful standardisation of the shaking and dilution, to compare the bacterial numbers in two or more samples of the same soil type, the figures obtained are only relative, and do not give an estimate of the total bacterial numbers of the soil.