So persistent a disturbing element in spring and autumn suggests that some physiological conditions underlie it, and that there is a real metabolic disturbance at these times of the year. So few continuous observations have yet been made on the metabolic processes of the body that it is not easy to verify such a surmise with absolute precision. Edward Smith's investigations, so far as they go, support it, and Perry-Coste's long-continued observations of pulse-frequency seem to show with fair regularity a maximum in early spring and another maximum in late autumn.[174] I may also note that Haig, who has devoted many years of observations to the phenomena of uric-acid excretion, finds that uric acid tends to be highest in the spring months, (March, April, May) and lowest at the first onset of cold in October.[175] Thus, while the sexual climaxes of spring and autumn are rooted in animal procreative cycles which in man have found expression in primitive festivals--these, again, perhaps, strengthening and developing the sexual rhythm--they yet have a wider significance. They constitute one among many manifestations of spring and autumn physiological disturbance corresponding with fair precision to the vernal and autumnal equinoxes. They resemble those periods of atmospheric tension, of storm and wind, which accompany the spring and autumn phases in the earth's rhythm, and they may fairly be regarded as ultimately a physiological reaction to those cosmic influences. FOOTNOTES: [128] F. Smith, _Veterinary Physiology_; Dalziel, _The Collie_. [129] Mondière, Art "Cambodgiens," _Dictionnaire des Sciences Anthropologiques_. [130] This primitive aspect of the festival is well shown by the human sacrifices which the ancient Mexicans offered at this time, in order to enable the sun to recuperate his strength. The custom survives in a symbolical form among the Mokis, who observe the festivals of the winter solstice and the vernal equinox. ("Aspects of Sun-worship among the Moki Indians," _Nature_, July 28, 1898.) The Walpi, a Tusayan people, hold a similar great sun-festival at the winter solstice, and December is with them a sacred month, in which there is no work and little play. This festival, in which there is a dance dramatizing the fructification of the earth and the imparting of virility to the seeds of corn, is fully described by J. Walter Fewkes (_American Anthropologist_, March, 1898). That these solemn annual dances and festivals of North America frequently merge into "a lecherous _saturnalia_" when "all is joy and happiness," is stated by H.H. Bancroft (_Native Races of Pacific States_, vol. i, p. 352).