Several excellent reviews of auxin matters have appeared during the past few years dealing broadly with the subject as a whole, such as the Wisconsin Symposium on Plant Growth Substances whleh is referred to repeatedly below, as well as reviews of more restricted scope such as those of Thimann (116) and of the previous volumes in this series.
The present review need not, therefore, attempt to cover the entire spectrum of auxin physiology. It will concern a few aspects of the subject only, aspects in which particular progress has been made in recent years. It will attempt to evaluate the work which has been done in each of the several fields, to see in how far an integrated picture can be made of each and to make a few suggestions
