An Improved Stain for Bacteria in Soil

A stain for bacteria in soil is proposed different from that originally employed in the introduction of pre-treatment of the soil smears with dilute acid. The procedure found best is: A suspension of soil in a 0.015% solution of gelatin is dried on a slide, treated 1-3 minutes in 40% acetic acid, washed and dried on a boiling water bath; while still on the water bath it is stained about one minute with 1% aqueous rose bengal. It is suggested however that under certain conditions better results may possibly be obtained by substituting hydrochloric for acetic acid and one of the phloxines or one of the erythrosins for rose bengal.