In May 1891 the report of an inquiry which had been instituted in the previous year into the working of the United Presbyterian College was submitted to the Synod.  The portion of it which referred to Principal Cairns’s department, and which was enthusiastically approved, concluded as follows:  “The Committee would only add that the whole present inquiry has deepened its sense of the immense value of the services of Dr. Cairns to the College, both as Professor and as Principal, and expresses the hope that he may be long spared to adorn the institution of which he is the honoured head, and the Church of which he is so distinguished a representative.”  The hope thus expressed was not to be fulfilled.

The specially heavy work of the preceding session—­the session in which, as already described, he had undertaken part of the work of the Church History class in addition to the full tale of his own—­had overtaxed his strength, and, acting on the advice of Dr. Maclagan and his Edinburgh medical adviser, he had cancelled all his engagements for the summer.  Almost immediately after the close of the Synod an old ailment which he had contracted by over-exertion during a holiday tour in Wales reappeared, and yielded only partially to surgical treatment.  But he maintained his cheerfulness, and neither he nor his friends had any thought that his work was done.  In the month of July he paid a visit to his brother David at Stitchel.  He had opened his brother’s new church there thirteen years before, and it had come to be a standing engagement, looked forward to by very many in the district, that he should conduct special services every year on the anniversary of that occasion.  But these annual visits were very brief, and they were broken into not only by the duties of the Sunday, but by the hospitalities usual in country manses at such times.  This time, however, there were no anniversary sermons to be preached; he had come for rest, and there was no need for him to hasten his departure.  The weather was lovely, and so were the views over the wide valley of the Tweed to the distant Cheviots.  He would sit for hours reading under the great elm-tree in the garden amid the scents of the summer flowers.  “I have come in to tell you,” he said one day to his sister-in-law, “that this is a day which has wandered out of Paradise.”  “We younger people,” wrote his niece, “came nearer to him than ever before.  He was as happy as a child, rejoicing with every increase of strength.  He greatly enjoyed my brother Willie’s singing, especially songs like Sheriff Nicolson’s ‘Skye’ and Shairp’s ’Bush aboon Traquair.’  We were astonished to find how familiar he was with all sorts of queer out-of-the-way ballads.  Never had we seen him so free from care, so genial and even jubilant."[21] The summer Sacrament took place while he was at Stitchel, and he was able to give a brief address to the communicants from the words, “Ye do shew forth the Lord’s death till He come,” in a voice that was weak and tremulous, but all the more impressive on that account.  One of his brother’s elders, a farmer in the neighbourhood whom he had known since his schooldays, had arranged that he should address his work-people in the farmhouse, and to this quiet rural gathering he preached what proved to be his last sermon.