On Saturday, 15 April, together with the participants of the Study Week on "Use of Fertilizers and its Effect in Increasing Yield with Particular Attention to Quality and Economy", the Pontifical Academy of Sciences convened for an Extraordinary Session during which Prof. Fritz Baade gave an interesting lecture on the subject of "Hundred years of increasing crops thanks to the use of commercial fertilizers - A retrospective view at the years 1900 an outlook on the year 2000" illustrated by numerous diagram projections.