These notes were most probably made when Beale was working in Indiana University, Bloomington, in Tracy Sonneborn's laboratory. At this time Beale was studying the change from serotype D to serotype B of stock 51 (variant 4). The cells were treated with an immunising and potentially lethal solution containing anti-D antibodies, which lead to the cells becoming 'resistant' to the immunising action. Tracy Sonneborn had previously shown that the 'sensitive' and 'resistant' types of cell were 'hereditary'. Beale demonstrated that this change involved a replacement of the initial antigen (D) by another one (B) which could take place in every cell which was treated, and that for an intermediate period, both antigens could be detected in a single cell. Beale published a paper on the subject in 1948 entitled 'The process of transformation of antigenic type in Paramecium' which appeared in the Proceedings of the National Academy of Science, USA (34, 418-423).