“…At the time when the Polyster WOL programme began, the subcutaneous injection of the test substance was considered to be an acceptable example of a stringent test and many scientists accepted this without question, However, despite the fact that benign or malignant cancer can certainly be produced in this way when a variety of chemicals are injected, there was a growing belief that this was not a suitable test (Roe, 1966;Food Protection Committee and Others, 1967;Shubik, Saffiotti, Lijinsky, Pietra, Rappaport, Toth, Rahn, Tomatis & Feldman, 1962). This subject has been dealt with at greater length by Philp (1968).…”