In the scheme of nature there appears to be a fixed law of cranial projection. The cranio-facial angle in man, ABC (as shown in diagram No. 1), is a right angle, and the gnathic angle ADE is approximately the same. The line FG represents the axis of the facial plane, and the line HI is the cervical axis. Reckoned from the vertical line KL it will be seen that the angles formed by the facial axis FG and the cervical axis HI are about the same on opposite sides of the vertical line KL. It will be observed that these lines and angles are those of man whose posture is upright. In diagram No. 2 it will be seen that both the facial axis FG and the cervical axis HI form a greater angle from the vertical line than in man. It will also be seen that the cranio-facial angle ABC is increased by about one-half of the angle of the facial axis GML. The gnathic angle ADE is increased in about the same degree. These are the lines and angles of the anthropoid apes. [Illustration: Diagram No. 2] [Illustration: Diagram No. 3] Diagram No. 3 represents the lines and angles of monkeys, in which the angles widened in a degree measured by the tendency of the animal to assume a horizontal posture. In diagram No. 4 we have the lines and angles of reptiles. In these it will be seen that the facial axis FG and the cervical axis HI are almost horizontal. The cranio-facial and gnathic angles have been correspondingly widened. [Illustration: Diagram No. 4] Man standing erect has the greatest range of vocal powers of any animal. He also has the greatest control over them. In vocal range the apes come next in order. As we descend the scale from man through apes, monkeys, lemurs, and lemuroids, ultimately ending in the reptilian forms, we find the vocal powers restricted in scope and degraded in quality, until in the lowest reptiles they are lost in a mere hiss. Concurrent with the variations described, the longitudinal, vertical, and transverse axes of the brain also change their proportion in a like degree. The angles formed by the plane of the vocal cords with the axis of the larynx undergo a corresponding change. A just deduction from these facts is, that the gnathic index ADE is a true vocal index. This rough outline of the law of cranial projection does not purport to be a full treatment of the many lines and angles correlated to the powers of speech, but the suggestions may lead the craniologist into new fields of thought. CHAPTER II Early Impression--What is Speech--First Efforts--The Phonograph--The First Record of Monkey Speech--Monkey Words--Phonetics--Human Speech and Monkey Speech