A METHOD OF STAINING BACTERIAL FLAGELLA

Abstract

It has been thought useful to give the details of a modification of Muir's method of demonstrating the flagella of bacteria, recently developed in this laboratory. The method has proved successul in staining the flagella of about one hundred strains of soil bacteria and has been tested on other common types such as B. coli, B. fluorescens, and B. mycoides. The process has given much more certain results than any of the standard methods tested and possesses the advantage that very little precipitate remains on the film surrounding the bacteria. CULTURES The best results are obtained with twenty-four-hour to three-day old slope cultures on nutrient agar or some other medium suited to active growth. (Nutrient agar in the case of the soil organisms upon which the stain was successful is composed of pepton 5 gr., Lemco 3 gr., and agar 15 gr. per litre of water; pH adjusted to 7.3.) Suspensions are made in sterile distilled water in a watch glass and left for twenty minutes to half an hour at room temperature, during which time the organisms if active will be washed free of slime. They should be examined for motility in the fresh state, immediately before the film is made. SIBDES Clean slides are kept in ammonia-alcohol; for use they are dried with a clean duster and flamed by passing 24 times through the Bunsen at the level of the top of the inner cone. They are then put into an oven at 450 to 50°C. to cool, flamed side uppermost. 273