The teacher must be an optimist. She is not self-deceived, she sees the faults of the girl in her teens. She is conscious of the thoughtlessness, the utter lack of courtesy, the love of the extreme in everything, and the greater faults of insincerity and pretense that characterize to so great an extent the girlhood of to-day. But while she is pained she is not dismayed. She is a good diagnostician. She examines her individual patients, finds the weak places, discovers the cause of the disease, and then goes to work systematically to eradicate it, trusting to the normal, unaffected organs and tissues to aid in restoring perfect health. She believes in and uses preventive measures and they pay. The teacher must herself be an example in thoughtfulness and courtesy, respectful to those higher in office, and willing to co-operate with, instead of criticizing, those who have plans by which they hope to add to the efficiency of the school as a whole. None of these things are lost upon the keen-eyed girl in her teens; indeed, the teacher’s dress, even the condition of her gloves, makes an impression and has an influence. It has become a truism that to be successful in teaching one must know the pupil; yet only last week I met a teacher anxious for a new course of study which would interest her class of girls sixteen and seventeen years of age, who revealed in conversation the fact that she knew practically nothing of the girl’s homes. She did not even know the section of the city in which many of them lived, had made no calls and could tell the occupation of only two of the fathers. She did not know for what the girls were preparing themselves, nor any of their hopes or desires, and she had taught the class for two years. She said the girls were not interested, and did not prepare assigned work. This type of teacher is fast disappearing, but wherever she exists the fact that the class seems to be “not interested” indicates very clearly that those who insist that _the teacher must know the girl_ are right. In the series of studies of the girl in her teens an article appeared in _The Sunday School Times_[1] giving the opinions of several hundred girls as to what constitutes “a lovely teacher,” and according to the statements of these girls, a lovely teacher is, “pleasant,” “fair to everybody,” “treats every one alike,” and “is interested in what you are doing.” “She writes notes to you when you are ill,” “calls on you,” “is kind and patient,” “makes the lesson interesting,” “explains what you don’t understand,” and “knows a great deal.” Upon these as necessary qualifications of “a lovely teacher,” the girl in her teens from all sorts of homes and from various parts of our country is agreed, and as we think about it we feel inclined to trust her analysis.