The PAS Plenary Session was held from 19 to 23 October with a rich high-level scientific program. The President, His Excellency Prof. Carlos Chagas, chaired the colloquium on "Science and the Modern World", which was divided into three sessions: "The role of science in the contemporary world” (Speaker: Prof. Marcel Roche); “A scientist’s training“ (Speaker: Prof. Alfred Ubbelohde); “The responsibilities of the scientist” (Speaker: Prof. Louis Leprince-Ringuet). The discussion was introduced by two co-rapporteurs and followed by high-level interventions by the participating Academicians.
Three public lectures were given by Academicians Prof. Paul Dirac on: "Heisenberg's influence on physics", Prof. Bengt Strömgren on: "L'évolution des galaxies dans l'univers en expansion" and Prof. Rita Levi-Montalcini on "New developments in neurobiology". Numerous papers were received, including those of the six new Academics who informed their colleagues of their most recent and important research.
On the last day of the Plenary Session, Prof. Lucio Luzzato, Director of the International Institute of Genetics and Biophysics in Naples and winner of the Pius XI Gold Medal, established by John XXIII to honour the memory of the Founder of the Academy, held a conference on the theme: "Genetics of red blood cells and human evolution".
On 23 October the Holy Father granted an audience to the Academicians and to the scientists taking part in the concurrent Study Week on “Natural Products and the Protection of Plants”.