understanding of the things concerning the king- dom of God. Before, however, anyone can decide the question of his " aptness to teach," he must have, by actual trial, determined whether or no he possesses this qualification. A man may be a genius of the highest order, be distinguished for the extent and accuracy of his theological scholar- ship, and still be far from " apt to teach." This I regard as a special attainment made by compara- tively few. It should not, therefore, be taken for granted, but its existence should be demonstrated by careful experiment in teaching. 1 have, you will perceive, given you but two ele- ments of a call to the ministry, but my sheet is full. Next week I shall direct your attention to a third. Yours affectionately, D. A. W. To a Thcoloyical SUidciit. 221 III. Dear Friend: — In my last I mentioned two elements of a call to the ministry — a desire for the work, and the necessary qualifications for it. 3. There is, however, a third which should not be overlooked. I mean opportunity. There may be this desire, there may also be native talent and no insuperable mental or moral disqualifications but opportunity may be lacking, and, as long as this is the case, a call cannot be regarded as complete.