Germination of spores of Bacillus cougulans, B. cereus and mixed soil spores in nonnutritive buffer, in rich laboratory media and in foods was accelerated, and the final amount of germination was increased, when germinants were added (e.g. L-alanine, L-or-aminobutyric acid, inosine, combinations of L-alanine with ribosides like guanosine and adenosine). Further potentiation of the rate and amount of L-alanine-initiated germination was caused by adding the inhibitor of alanine racemase, o-carbamyl-D-serine. The germination rate always decreased markedly after about the first 10or 100-fold fall in level of surviving ungerminated spores, in keeping with the concept that populations of bacterial spores are heterogeneous as regards germinability of the individual spores. Although the presence of the germinants and potentiators of germination lowered the levels of spores remaining ungerminated after incubation in various media and foods, a superdormant fraction of the spore populations always remained. The limitations imposed by superdormancy on the use of initiation of germination as a step in spore destruction processes are highlighted, and some difficulties in the study of superdormant spores are discussed.