The following quotation from Jennings well illustrates the principle of conservation of power we are here attempting to make clear: "In the course of my 'let alone' practice, I have many times been astonished to see to what lengths the economy of life could carry the reduction of active processes, and yet restore the machine to new and vigorous animation. Many times have I stood by my patients and seen their eyes closed apparently in death, and yet had the satisfaction of witnessing their return to life and health. To what extent it might be expedient and practicable, in some cases, under the most favorable circumstances, for the vital economy to carry this suspension of all vital action within scope of human ken, and then have it issue in reanimation, it is of course impossible for any man, with his present limited means of knowledge on the subject, to form even a satisfactory conjecture. But I have no doubt that if the theory of unity of vital action prevails, and the practice of leaving the work of renovating the human system in the hands of nature, under such circumstances as further light and experience shall dictate, it will be found to occur occasionally that persons will lie for days and even weeks, to all human appearance within the cold domains of death, and after all be restored to her friends and society on earth. Under the present system of managing disease and interments, it is no unheard of thing for persons to be apparently dead for some length of time, and resuscitate."--Medical Reform, p. 294.

To the author there seems little room to doubt that cases of apparent death from which recovery follows, represent merely an extreme outworking of this same principle of conservation through rest. Perhaps the condition, like that of suspended animation, seen in many plants and animals, is a state in which the sick organism is capable of maintaining the status quo in face of conditions unfavorable to active life. It is a means of passive defense; a strategic retreat. Let us say it is analogous to sleep, yet it goes beyond any mere reduction or even suspension of functions seen in sleep.

The recuperative or renovating work never begins but once--with the beginning of life--and it never ends until life ends. There is but one difference between this work in "disease" and in health. In health there are sufficient vital energies to sustain all the organs and functions of the body, while in disease, there is not sufficient energies to sustain all these functions adequately to meet the ordinary demands of life. And this lack of power, or disproportion between work to be done and ability to work is the fundamental reason for "disease".

The laws or principles on which "disease" action is conducted are precisely the same as those upon which healthy action depends--namely, to use what power the system possesses, be it much or little, in the highest interest of the organism. This principle will not permit a single function, however small or relatively unimportant, to be unnecessarily reduced or disturbed in its conduct. So long as it can repair damages and waste without depriving the cardinal organs of sufficient force to conduct their work, it will do so. But should it become necessary to enforce the Law of Limitation in respect to these organs and diminish their power so that their action is enfeebled, in order that the power may be used elsewhere, the change will be cautiously made and conducted with the greatest regularity if not interfered with. The "old order" will be restored in the same lawful and orderly manner, as soon as the end for which the change was made has been attained.