Among the manipulable outputs (muscular groups) I would include those of respiration and phonation. The dexterous and finely differentiated use of these muscles generates all the complexities of human speech. As more of the physiology and psychology of human speech are analyzed and made part of our sciences, the sharper will be our criteria for separating man from the other animals, and from those with smaller brains. Scientific descriptions of human speech are of relatively recent origin. Scientific descriptions of the physiology of the vocal tract are anything but a closed book at the present time. The neuroanatomy and neurophysiology of speech is in a relatively primitive state of development as a science. With such a lack of knowledge of the intimate and detailed mechanisms concerned, it would be rather presumptuous to evaluate at the present time their role in the measurement and testing of intelligence and intellectual capacity. However, I wish to point out that these factors are important in such an evaluation and become even more important in terms of evaluating a species that is not human. Thus it is necessary, in order to evaluate the intelligence of even the dolphins, much less the whales, to know something of their abilities in the areas of phonation and other kinds of bodily gestures and manipulations and hence in their abilities to communicate with one another. As I implied in _Man and Dolphin_, it is not possible to measure accurately the intelligence of any other being than that of a human being, mainly because we do not exchange ideas through any known communication mode with such beings.