Since abstracts of the papers in this discussion have been circulated, I assume that it is unnecessary to explain that the title does not refer to the biochemical steps that result in the fixation of atmospheric nitrogen, but to the well-known saying that ‘a child must learn to walk before it runs’. As an introduction to the summaries of present day research, it seems worth-while to furnish a perspective of some of the events that led to the modern studies that have been made possible by the development of cell-free systems capable of fixing N 2 . This contribution will be limited primarily to those steps that are most closely related to the subject matter of the biochemical papers on the programme. This choice is dictated, not only because of the limits of time but also because these papers represent the area of my own research interests and, presumably, then, the area of my greatest competency. Alone, perhaps this would not be enough, but if the personal participation that furnishes background dealing with items of human interest and errors—observations that never get into the published works—is added, it should suffice. Other aspects in the field are represented in the discussion by the contributors of the afternoon portion of the programme; but having heard three of these recently, I am confident that these papers, too, will have a biochemical component.

No abstract