gland, the accessory thyroids, the sexual glands, the suprarenal bodies, and so on, we get definite degenerative phenomena appearing. In many instances, indeed, the absence of these organs is incompatible with life itself. The same phenomenon manifests itself when the organ is left in its proper place, but through some cause or other gradually discontinues its proper functions. In such cases there is no need for the organ to be destroyed; it is sufficient if the production of a specific secretion entirely ceases, a condition which is equivalent, to a certain extent, to the complete absence of the organ. These observations, which are supplied to us by pathology, together with facts which may be produced at any time—as when we extirpate certain organs and, after the results of such extirpation have manifested themselves, make a fresh transplantation—give an extremely varied picture of the reciprocal relations of the different organs towards each other.
Each group of cells—each organ—has certain functions to fufil in regard to the rest of the cell organization, and in this respect it possesses a certain independence of its own. There are also, of course, reciprocal relations within the cells themselves of an organ. Many observations point to the possibility that apparent morphological unity of an organ does not always mean unity of function. The independence of a given organ is only a relative one. As we have
