In the session of 1753–54, his father (Alexander Monro "primus") found his class too large for the lecture room and had to divide the class, repeating his lecture in the evening. This he found difficult, and he experimented with his son (Alexander Monro "secundus" taking the evening class. The results were satisfactory and so he presented a petition to the Town Council at the close of the session asking them to appoint his son formally as his successor. This petition was granted on 10 June and Alexander Monro "secondus" was admitted as conjunct professor on 11 July.