One of the services which Mr. S. A. Handford has rendered to classical teaching in this country is his adoption of the word ‘habit’, rather than ‘rule’, as applied to the sequence of tenses in Latin. 1 For to most people, and especially to the learner, the word ‘rule’ has the finality of something which must be obeyed. But ‘rules’ of grammar and rules of conduct are very different things. Grammar is the systematic analysis of phenomena observed in a language, and a grammarian's ‘rules’ are simply the formulation of habitual modes of expression which he has observed in the language which he is studying. If his observation has been faulty or incomplete, the ‘rule’ which he formulates may be inadequate or false. And so a ‘rule’ which appears to run counter to common sense must provoke suspicion.