Abstract
i) A general theory for the frequency distribution of the number of mutants per individual has been developed on the basis of proper assumptions.
ii) The conditions for leading to a Poisson distribution of the number of mutants have been obtained.
iii) The comparison of the theory with the experiments which disclosed an appreciable deviation from a Poisson distribution shows excellent agreement. The occurrence of mutants in a large cluster is also in good agreement with the calculated frequency.
iv) A method for estimating the number of germ cells present when treated with a mutagenic agent has been proposed. The estimated number of germ cells is in agreement with the observed number of the irradiated silkworm gonia.
v) A connection of cluster mutants and sample size of germ cells (used for recovery of mutations) per individual with the estimated mutation rate has been discussed.
