In the other course, on Christian Evidences, he did not include any discussion on Theism which--probably because of his special familiarity with the Deistical and kindred controversies, and also because the modern assaults on supernatural Christianity from the Evolutionary and Agnostic standpoint had not yet become pressing--he postulated. And, discarding the traditional division of the Evidences into Internal and External, he classified them according to their relation to the different Attributes of God, as manifesting His Power, Knowledge, Wisdom, Holiness, and Benignity. With this course he incorporated large parts of his unfinished treatise on "The Difficulties of Christianity," which, after he had thus broken it up, passed finally out of sight. The impression which he produced on his students by these lectures, and still more by his personality, was very great. "I suppose," writes one of them, "no men are so hypercritical as students after they have been four or five years at the University. To those who are aware of this, it will give the most accurate impression of our feeling towards Dr. Cairns when I say that, with regard to him, criticism could not be said to exist. We all had for him an appreciation which was far deeper than ordinary admiration; it was admiration blended with loyalty and veneration."[16] Specially impressive were the humility which went along with his gifts and learning, and the wide charity which made him see good in everything. One student's appreciation of this latter quality found whimsical expression in a cartoon which was delightedly passed from hand to hand in the class, and which represented Dr. Cairns cordially shaking hands with the Devil. A "balloon" issuing from his mouth enclosed some such legend as this: "I hope you are very well, sir. I am delighted to make your acquaintance, and to find that you are not nearly so black as you are painted." [Footnote 16: _Life and Letters_, p. 560.]