ABSTRACT
IN RECENT years a considerable body of evidence has accumulated for the existence in the cytoplasm of bodies of a more or less gene-like nature. Geneticists have been particularly active in investigating them and have referred to them by a variety of names, such as plasmagenes, cytogenes, blastogenes, proviruses, etc. The £rst has been the most commonly accepted, and will be used here in a rather wide sense, to cover several rather different types of gene-like entities.
