This new departure in teaching did not interfere with the continuation and extension of field-work, which up to this time had been the form of practical study cultivated in Edinburgh. On the contrary the Botanical Excursion gave Balfour an outlet for energy and favourable opportunity for the exercise of those gifts of personal magnetism and intellectual stimulus through which he influenced and guided many generations of students. Every Saturday during the summer session an excursion was made, and one of some days' duration usually brought the session to a close. Through these excursions the greater part of Scotland was traversed—on one occasion the terminal excursion of the session was to Switzerland—and the features of flora and vegetation were brought to the attention of many hundreds of students.
The aim and result of the excursion were not solely the acquisition of plants and their identification. The stimulating effect on many of this side of Botany is evidenced even in our day by the zeal with which search after rare plants is pursued, and in the eagerness displayed in the race after micro-forms. But the enticement of acquisition and discovery of novelty whilst there were not the governing influences in Balfour's excursion. In touch as he was with the problems of organography in its fullest sense, a man of wide reading familiar with the botanical work of his time, and associated as he had been in the field with men like Edward Forbes and Hewett Cottrell Watson, Balfour could and did look at plants from the standpoint of their place in vegetation, and in relation to the conditions of growth, and as having a history in their habitat. His teaching reflected this. It was never classification, diagnosis, and nomenclature as the end-all of Botany. The details emphasised changed as the progress of botanical discovery gave new clues to explanation of form and relation, and it was the solvings and attempts at solvings of observed phenomena that gave that fascination to his excursions, the remembrance of which seems to have clung to those who had the fortune to join them. The succession of plants and plant-form from base to summit of a highland hill; contrasts of vegetation of stream-course, mountain pasture, alpine rock; high mountain forms of shore plants; intrusion
