The quantitative and qualitative changes in the particular groups of humic acids in peat—muck soils, in the course of their drying were examined. It was found that 99% of organic matter of these soils is constituted by the light fraction which increases in the course of peat transformation. The degree of humification of organic matter and the ratio of the humic to fulvic acid carbon increase with the drying of the site.
In patients with parodontium lesions infected and not infected with Trichomonas tenax the follwing indices were analysed: caries index, Russell's index (parodontium diseases), Greene-Vermillions index (oral hygiene). No statistically significant differences were found between infected and non-infected groups as regards caries and oral hygiene. Russell's index showed considerable differences between the groups of subjects.