Measured amounts of soils were suspended in melted agar and drops of the agar suspension were allowed to solidify on hemacytometer slides to give films of known depth. The films were dried, stained with acetic-aniline blue, dehydrated, mounted in euparol and the number of organisms counted in known areas. The absence of lateral shrinkage and the known thickness of the film allowed the total number of organisms per unit of soil to be calculated The frequencies of bacterial colonies and mycelial fragments formed a Poisson distribution; those of the number of bacteria per colony formed a logarithmic series; and those of the total number of bacteria per field fell into a negative binomial distr.