Fifty years of plant hormone research.

Plant physiology as a whole, of course, has developed enormously in 50 years, and most of its journals have been born in that time. But perhaps the growth has been greater in the hormone field than in any other because the 50 years have seen not only the growth of knowledge but a change in outlook. The enthusiasm with which people have flung themselves into the field, after a long lag in the early years, is like that with which people crowded into the field of DNA and molecular genetics, and perhaps the reasons are much the same, viz. that in both fields we are dealing with the control system. When we can manipulate the controls we feel we are close to the heart of the organism's secrets. Also, applications are often rather direct. The hormone field has reached its present level of understanding from somewhat confused beginnings and through many twists and turns. A historian of science inevitably tends to give a picture of an orderly linear development of experiments and ideas, but such a picture would be quite misleading here.