This section is from the book "The Hygienic System: Fasting And Sun Bathing", by Herbert M. Shelton. Also available from Amazon: The Hygienic System Vol III Fasting and Sun Bathing.
Dr. Oswald says: "A germ disease, as virulent as syphilis, and long considered too persistent for any but palliative methods of treatment (by mercury, etc.), was radically cured by the fasting cures, prescribed in the Arabian hospitals of Egypt, at the time of the French occupation. Avicena already alludes to the efficacy of that specific, which he seems to have employed with similar success against smallpox, and Dr. Robert Barthlow, a stickler for the faith in drugs, admits that 'it certainly is an eminently rational expedient to relieve the organism of a virus by a continuous and gradual process of molecular destruction and a renewal of the anatomical parts.' Such is the hunger-cure of syphilis, an Oriental method of treating that disease. Very satisfactory results have been attained by this means." The point here is that the body tears down the defective parts and eliminates them during the fast, and then builds anew after the fast. With no digestive drudgery on hand, as Dr. Oswald expressed it, nature employs the long desired leisure for general house cleaning purposes. The accumulations of superfluous tissues are overhauled and analyzed; the available component parts are turned over to the department of nutrition, while the refuse is thoroughly and permanently removed. That this is true will become very apparent as we progress with our study of fasting.
"The organism, stinted in its supply of vital reserves," says Dr. Oswald, "soon begins to curtail its current expenditure. The movements of the respiratory powers decrease;--and before long the retrenchment of the assimilative function reacts on the intestinal organs. The colon contracts and the smaller intestines retain all but the most irritating ingesta."
Dr. Shew explained that "the principle on which the hunger cure acts is one on which all physiologists are agreed, and one which is readily explained and understood. We know that, in animal bodies, the law of nature is for the effete and worn-out and least vitalized matter first to be cast off. We see this upon the cuticle, nails, hair, and in the snake casting off its old skin. Now, in wasting or famishing from want of food, this process of elimination goes on in a much more rapid manner than ordinarily, and the vital force which would otherwise be expended in digesting the food eaten acts now in expelling from the vital domain whatever morbific matters it may contain. This, then, is a beautiful idea in regard to the hunger cure--that whenever a meal of food is omitted, the body purifies itself this much from disease, and it becomes apparent in the subsequent amendment, both as regards bodily feeling and strength. It is proved also in the fact that, during the prevalence of epidemics those who have been obliged to live almost in a state of starvation, have been free from attacks, while the well-fed have been cut off in numbers by the merciless disease."