VARIATIONS IN COUNTS OF LACTOBACILLI MADE FROM SINGLE SPECIMENS OF SALIVA

Series of plates, each made from single specimens of saliva, with extreme care in measurement, gave colony counts which varied over wide ranges. Different methods of mixing the original specimens were employed in an effort to secure better distribution of the organisms. Hand shaking, an amalgam mixer, a Kahn tube shaker, and 3 types of beaters were used. None of these increased the uniformity of counts. More consistent results were obtained when 5 cc. of the original specimen were placed in an equal amount of fluid agar and beaten before a second dilution was made and the specimen plated. All methods used gave some series showing wide variations.

The assemblage of the data from each cooperator emphasized the wide range of counts obtainable from a single specimen. It is obvious that, while trends are apparent in the lactobacillus counts of individuals, conclusions as to hourly or daily fluctuations are unjustified when based on single counts or series of counts such as used in this study.