Analysis of interactions between treatments applied concurrently onto biological systems

A program, written in BASIC, has been developed to analyse results of experiments studying individual and combined effect of two treatments (physical or chemical) on a biological system. Analysis is done in regard to: (1) level of significance selected for statistical test; (2) number of data available; (3) expected combined effect of treatments resulting from addition which is computed using an original formula; (4) experimental hypothesis tested. Using this program we have determined that there is a highly significant synergism between ampicillin (antibiotic) and amprolium (antiparasitic drug) to reduce the growth of some enteric bacterial strains which have a plasmidic resistance to ampicillin. Other applications are suggested.