Dr. W.B. Powell, in his work on "The Human Temperaments," announces the discovery of a measurement which indicates the tenacity of life, and the vital possessions of the individual. He has observed that some persons of very feeble appearance possess remarkable powers of resistance to disease, and continue to live until the machinery of life literally wears out. Others, apparently stronger and more robust, die before the usual term of life is half completed. He also noticed that some families were remarkable for their longevity, while others reached only a certain age, less than the average term of life, and then died. He remarked also that some patients sank under attacks of disease, when, to all appearances, they should recover, and that others recovered, when, according to all reasonable calculations, they ought to die. He, therefore, not only believed that the duration of human life was more definitely fixed by the organization than is supposed, but he set himself to work to discover the line of life, and the measure of its duration. He made a distinction between vital vigor, and vital tenacity. _Vital vigor_ he believed to be equivalent to the condition of vitality, which is indicated by the breadth of the brain found in the sanguine temperament; and _vital tenacity_ to be measured by the _depth_ of the base of the brain. Dr. Powell was an indefatigable student of nature, and followed his theory through years of observation, and measured hundreds of heads of living persons, in order to verify the correctness of the hypothesis. His method of measuring the head may be stated as follows: He drew a line from the occipital protuberance on the back of the head to the junction of the frontal and malar bones, extending it to a point above the center of the external orbit of the eye, near the termination of the brow. Then he measured the distance between this line and the orifice of the ear and thus obtained the measure indicating the vital tenacity or duration of, life. Fig. 88 is a representation of the skull of Loper, who was executed for murder in Mississippi. He might have attained a great age, had not his violent and selfish faculties led him into the commission of crime. In this illustration, B represents the occipital protuberance, and A the junction of the frontal and malar bones at the external angle of the eye. The distance between this line (A B) and the external orifice of the ear, is the measure of the life-force of Loper at the time of his: execution. [Illustration: Fig. 88.] [Illustration: Fig. 89.]