This section is from the "Nature Cure: Philosophy and Practice Based on the Unity of Disease and Cure" book, by Henry Lindlahr.
For many years past, physicians of the different schools of medicine, diet experts and food chemists have been divided on the question whether or not mineral substances which in the organic form enter into the composition of the human body may safely be used in foods and medicines in the inorganic form.
The medical profession holds almost unanimously that this is permissible and good practice, so that nearly every allopathic medical prescription contains some such inorganic substance, or worse than that, one or more virulent mineral poisons, as mercury, arsenic, phosphorus, etc.
So far, the discussion about the usefulness or harmfulness of inorganic minerals as foods and medicines was largely theoretical and controversial. Neither party had positive proofs for its contentions.
But Nature's records in the iris of the eye settle the question for good and for ever. One of the fundamental principles of the science of Diagnosis from the Eye is that "nothing shows in the iris by abnormal signs or discolorations except that which is abnormal in the body or injurious to it." When substances which are uncongenial or poisonous to the system accumulate in any part or organ of the body in sufficient quantities, they will indicate their presence by certain signs and abnormal colors in the corresponding areas of the iris.
In this way Nature makes known by her records in the eye what substances are injurious to the body, and which are harmless.
Certain mineral elements, such as iron, sodium, potassium, calcium, magnesium, phosphorus, sulphur, etc., which are among the important constituents of the human body, may be taken in the organic form in fruits and vegetables, or in herb extracts and the vitochemical remedies, in large amounts, in fact, far beyond the actual needs of the body, but they will not show in the iris of the eye, because they are easily eliminated from the system.
If, however, the same minerals be taken in the inorganic form in considerable quantities, the iris will exhibit certain well-defined signs and discolorations in the areas corresponding to those parts of the body in which the mineral substances have accumulated.
Obviously, Nature does not intend that these mineral elements should enter the organism in the inorganic form, and therefore the organs of depuration are not able to neutralize and eliminate them.
Thus, for instance, any amount of iron may be taken in vegetable or herb extracts, or in the vitochemical remedies, but this will not be seen in the eye. Whatever is taken in excess of the needs of the body will be promptly eliminated.
If, however, similar quantities of iron be taken for the same length of time in the inorganic, mineral form, the iron will accumulate in the tissues of stomach and bowels, and begin to show in the iris in the form of a rust brown discoloration in the corresponding areas of the digestive organs, directly around the pupil.
In similar manner sodium, which is one of the most important mineral elements in the human body, if taken in the inorganic form, will show in a heavy, white rim along the outer edge of the iris. Sulphur will show in the form of yellowish discolorations in the area of stomach and bowels. Iodine in the medicinal, inorganic form, prepared from the ash of seaweeds, shows in the iris in well-defined bright red spots. Phosphorus appears in whitish streaks and clouds in the areas corresponding to the organs in which it has accumulated.
An interesting exception to this rule is our common table salt (sodium chloride), which is an inorganic mineral combination. So far, diagnosticians from the eye have not discovered any sign in the iris for it. There seems to be something in its nature that makes it akin to organic substances or, like other inorganic minerals and their combinations, it would show in the iris.