Returning to his house, he always entered it by the back door, apparently because he did not wish to put the servant to the trouble of going upstairs to open the front door for him. It does not seem to have occurred to him to use a latch-key. In the evening there was generally some meeting to go to, but after his return, when evening worship and the invariable supper of porridge and milk were over, he always went back to his study, and its lights were seldom put out until long past midnight. Although his reading in these solitary hours was of course mainly theological, he always kept fresh his interest in the classical studies of his youth. He did not depend on his communings with Origen and Eusebius for keeping up his Greek, but went back as often as he could find time to Plato and to the Tragedians. Macaulay has defined a Greek scholar as one who can read Plato with his feet on the fender. Dr. Cairns could fully satisfy this condition; indeed he went beyond it, for when he went from home he was in the habit of taking a volume of Plato or Aeschylus with him to read in the train. One of his nephews, at that time a schoolboy, remembers reading with him, when on a holiday visit to Berwick, through the _Alcestis_ of Euripides. It may have been because he found it necessary to frighten his young relative into habits of accuracy, or possibly because an outrage committed against a Greek poet was to him the most horrid of all outrages; but anyhow, during these studies, he altogether laid aside that restraint which he was usually so jealous to maintain over his powers of sarcasm and invective. He lay on the study sofa while the lesson was going on, with a Tauchnitz Euripides in his hand; but sometimes, when a false quantity or a more than usually stupid grammatical blunder was made, he would spring to his feet and fairly shout with wrath. Only once had he to consult a Greek lexicon for the meaning of a word; and then it turned out that the meaning he had assigned to it provisionally was the right one. A Latin lexicon he did not possess.