Colin Maclaurin,* the famous mathematical professor of Edinburgh College, was an able expounder of Newton's Principia. Indeed, Newton was so impressed with him that he had offered to pay his salary himself.
Maclaurin suffered from a physical affliction: he always dislocated his jaw and was unable to shut his mouth whenever he yawned. His pupils took advantage of this. When tired of his lecture, they either began to yawn or open their mouths in imitation of that act. This proved so infectious that the professor began to yawn too. He stood before them with his mouth open and could not proceed till he rang for his servant to come and shut it. In the meantime, the mischievous enemies of Euclid effected their escape.
愛丁堡學院著名數學教授科林．麥克勞林*擅長闡繹牛頓的《原理》，牛頓對他十分欣賞，曾提議說，麥克勞林的薪水，由他自掏腰包支付。
麥克勞林肉體上有一事引以為苦：他一打呵欠，下顎就會脫臼，嘴巴再也合不攏。他的學生於是利用這一點，聽課聽到沒趣，就打呵欠，或張嘴作打呵欠狀。麥克勞林受他們感染，也會跟着打呵欠，嘴巴再也合不上，站在學生跟前，無法繼續講課，直到僕人聽見他響鈴，前來幫他合上嘴巴。那些惡作劇的幾何學叛徒就乘間逃遁。
*麥克勞林生於一六九八年，卒於一七六四年。