Phenocopies.

Phenocopies by Heat Treatment Goldschmidt (1935) proposed the concept of phenocopy for what he thought to be 21 different types of abnormal wings and 10 different types of abnormalities of bristles, eyes, and other organs produced by heat treatment of Drosophila larvae. He expressly stated: 'The enumeration shows al- ready that the phenotypes of the great majority of mutants known in Drosophila can be produced in these experiments as non-genetic modifications. I do not doubt that in fact any phenotype of any mu- tant may be copied in this way if we succeed in creating still more possibilities of influence by further modifications of experimental conditions.'