If these theories be true, heat may no longer be regarded as actual motion among the particles of heated matter, neither may we longer imagine the existence of hypothetical upper trade winds. If these theories be true, the part which has ever been attributed to the sun as originator and dispenser of light and heat, has been overestimated. Every sphere contains within its enclosure the source from which its own supply is derived;--a veritable storehouse, which at one and the same time yields and governs its requisite supply. _The earth receives what is due to it, in the interchange constantly taking place_; and not an amount which the sun may fitfully dole out. In the character of the winds, and atmosphere as disclosed, what revelations! What floods of light will thus be thrown upon subjects now mysterious! FOOTNOTES: [14] Appendix, p. 106. [15] Appendix, p. 106. CHAPTER XIII. THE DIRECT INFLUENCE OF THESE FORCES AS CAUSATION OF DISEASE. In its bearings upon the systemic conditions which we term health and disease, this mysterious vito-magnetic fluid is of the highest import. This great principle which fills the earth and all spheres, and governs and binds them together--this great principle which is the source of all life, animate and inanimate--this principle dominates in every vital system, from man down through and beyond the microscopic forms of existence. The normal action of this principle in every part of the human system constitutes _health_; its abnormal action, _disease_; its interruption, _death_. The human system is thus a delicately organized and exceedingly sensitive vito-magnetic machine, and is virtually kept in action through the operation of this principle. Any condition, therefore, which may directly or indirectly influence or disturb this principle, may influence or disturb the actions of every human organization. In the search for causes of disease throughout the ages, this field, so fruitful in material, has been left almost unexplored. The disclosures of the early future will wonderfully change the sentiments entertained in regard to the cause of a large proportion of our diseases. Meteorological influence, although now comparatively ignored as a disease-producing power, will ere long be recognized not only as _a_ power, but as _the_ power, far overshadowing all other influences combined. The character and extent of these influences are scarcely imagined. In estimating them the attention of the profession is now mainly directed to thermometric and hygrometric changes and conditions. These form not the largest proportion of the perturbing influences constantly in operation around us.