The least amount of quenching constituent,Qm,required to produce self‐quenching action in counters filled with rare gas‐polyatomic gas or vapor mixtures, was measured as a function of cathode radius and total pressure for methane, butane, and ethyl acetate in helium, neon, and argon. It was found that the variation ofQmwith cathode radius and with total pressure was in accord with the Korff‐Present theory of quenching action for counters of this type. From these minimum amounts necessary to quench, the average least number of collisions,M12, required to affect electron transfer between the rare gas ions and polyatomic molecules, was calculated for each of the nine mixtures used.M12was found to vary from about 1 collision/transfer for the ethyl acetate‐neon mixture, to over 1000 collisions/transfer for the methane‐helium mixture. The order of decreasing values ofM12in each of the three rare gases used was methane, butane, and ethyl acetate, while the order of decreasing values ofM12for any one polyatomic substance in the three rare gases was helium, argon, and neon. An attempt is made to explain these results using the theory for exchange of charge between atomic ions and molecules formulated by Kallmann and Rosen.