The preparation of this work occupied the best part of his time for the next three years, the first volume appearing in 1880, the second in 1881.
In the autumn of 1880, he attended the Meeting at Swansea of the British Association for the Advancement of Science, having been appointed Vice-President of the Biological Section with charge of the Department of Anatomy and Physiology. At the Meetings of the Association, especially of late years, much, perhaps too much, is expected in the direction of explaining the new results of science in a manner interesting to the unlearned. Popular expositions were never very congenial to Balfour, his mind was too much occupied with the anxiety of problems yet to be solved; he was therefore not wholly at his ease, in his position on this occasion. Yet his introductory address, though not of a nature to interest a large mixed audience, was a luminous, brief exposition of the modern development and aims of embryological investigation.
During these years of travail with the _Comparative Embryology_ the amount of work which he got through was a marvel to his friends, for besides his lectures, and the researches, and the writing of the book, new labours were demanded of him by the University for which he was already doing so much. Men at Cambridge, and indeed elsewhere as well, soon began to find out that the same clear insight which was solving biological problems could be used to settle knotty questions of policy and business. Moreover he united in a remarkable manner, the power of boldly and firmly asserting and maintaining his own views, with a frank courteousness which went far to disarm opponents. Accordingly he found himself before long a member of various Syndicates, and indeed a very great deal of his time was thus occupied, especially with the Museums and Library Syndicates, in both of which he took the liveliest interest. Besides these University duties his time and energy were also at the service of his College. In the preparation of the New Statutes, with which about this time the College was much occupied, the Junior Fellows of the College took a conspicuous share, and among these Junior Fellows Balfour was perhaps the most active; indeed he was their leader, and he threw himself into the investigation of the bearings and probable results of this and that proposed new statute with as much zeal as if he were attacking some morphological problem.