I was particularly struck with the fact that when asking for food by the word _mum_ he gave to it (I will copy the words written down at the time), “a most strongly marked interrogatory sound at the end.” He also gave to “Ah,” which he chiefly used at first when recognizing any person or his own image in a mirror, an exclamatory sound, such as we employ when surprised. I remark in my notes that the use of these intonations seemed to have arisen instinctively, and I regret that more observations were not made on this subject. I record, however, in my notes that at a rather later period, when between eighteen and twenty-one months old, he modulated his voice in refusing peremptorily to do anything by a defiant whine, so as to express, “That I won’t;” and again his humph of assent expressed, “Yes, to be sure.” M. Taine also insists strongly on the highly expressive tones of the sounds made by his infant before she had learned to speak. The interrogatory sound which my child gave to the word _mum_ when asking for food is especially curious; for, if any one will use a single word or a short sentence in this manner, he will find that the musical pitch of his voice rises considerably at the close. I did not then see that this fact bears on the view which I have elsewhere maintained that before man used articulate language, he uttered notes in a true musical scale, as does the anthropoid ape Hylobates. Finally, the wants of an infant are at first made intelligible by instinctive cries, which after a time are modified in part unconsciously, and in part, as I believe, voluntarily as a means of communication,--by the unconscious expression of the features--by gestures and in a marked manner by different intonations,--lastly by words of general nature invented by himself, then of a more precise nature imitated from those which he hears; and these are acquired at a wonderfully quick rate. An infant understands to a certain extent, and as I believe, at a very early period, the meaning or feeling of those who tend him, by the expression of their features. There can hardly be a doubt about this with respect to smiling; and it seemed to me that the infant whose biography I have here given understood a compassionate expression at a little over five months old. When six months and eleven days old, he certainly showed sympathy with his nurse on her pretending to cry. When pleased after performing some new accomplishment, being then almost a year old, he evidently studied the expression of those around him. It was probably due to differences of expression and not merely of the form of the features that certain faces clearly pleased him much more than others, even at so early an age as a little over six months. Before he was a year old, he understood intonations and gestures, as well as several words and short sentences. He understood one word, namely, his nurse’s name, exactly five months before he invented his first word, _mum_; and this is what might have been