This is the cause of numerous diseases, most of which are due either to overproduction or underproduction of the secretion which regulates numerous functions of the body. 7. _The tooth and eye tissue_: While very different in external appearance, functions and physical qualities, the teeth and the eyes have nevertheless, the most important part of their chemical composition in common; namely, _the fluoric acid_, which distinguishes them from all other tissues. In the process of natural healing the replacing of any element lacking through destructive causes in either tissue will practically be the same. 8. _The hair tissue_: Certain chemical component elements are only found in the tissue which is called the hair, and which receives its nourishment like all other tissues, through the blood. While the hair may seem to be in apparently slight connection with the rest of the body, it is in reality, none the less an organic portion of the same, and dependent, like the rest upon the same central system of supply. 9. _The skin tissue_: With reference to this tissue, much the same remarks apply as already mentioned in regard to the mucous membrane. It, however, has certain chemical elements, which are characteristic to its various layers. Since the skin forms the most important intermediary between the external elements and the chemical and structural elements of the interior of the human body, it is of the greatest importance that its chemical composition should always be correct, and that it should not be subject to decomposition such as improper nourishment engenders. It should be borne in mind that the skin, like all other organs of the body, grows from the inside outward, so that any ailment concerning the skin, which is not of a traumatic nature, must be based upon wrong or insufficient nourishment, and cannot be cured in any other way than by internal regenerative means. 10. _The gelatigenous tissue_: This tissue, chemically and otherwise peculiar as it is, forms the chief component part of many of the human organs, and it may be truly said that the lack of attention which its peculiarities have received in the past is responsible for more disease and its fatal issue than almost anything else. The gelatigenous tissue contains a number of special component elements, which require special nourishment through proper diet; and in view of the fact that the gelatigenous tissue pervades so many of the various organs, its effect upon the functional abilities of a great number of them is obvious. The elasticity of most organs which work by contraction and expansion, depends entirely upon the gelatigenous, rubber-like tissue of which they are so largely composed. 11. _The cartilage tissue_: Practically the same applies to the cartilage tissue; but it is only recently that it has been found to what extent this is the case.