The same: “Untersuchungen über die electrische Nervenreizung.” Braunschweig 1864. [38] _Max Verworn_: “Untersuchungen über die polare Erregung der lebendigen Substanz,” etc. III Pflügers Arch. Bd. 62, 1896. Two effects can be realized by the alteration in the living system as the result of prolonged stimulation. Either a new state of equilibrium is established by the prolonged action, or sooner or later death develops. In considering both results, however, we will ignore for the present the fact that every living system in the absence of such prolonged stimulation is always in a state of change, i.e., development. Only with this restriction can an equilibrium of the living system be spoken of. [Illustration: A Fig. 7. B _Orbitolites complanatus._ A--Before stimulation. B--Under influence of a constant current.] It is sometimes the case that under the influence of a stimulus a new equilibrium is developed, which may remain as long as the stimulus persists. This most frequently occurs as a result of _weak_ stimuli. That which is usually termed “individual adaptation” belongs in this category. Likewise some of the natural and artificial immunizations may also be included. The continued stimulation in such cases of adaptation as we learned before in the example of _Amœba limax_ and _radiosa_ or _Branchipus stagnalis_ and _Artemia salina_ becomes a vital condition for the living substance in its new state. The other result, namely, that of death ensuing sooner or later, is most frequently produced by stronger stimulation. Through the effect of the prolonged stimulation, the change in the living system is so great that all harmonious interaction of the various processes of life become after a time impossible. The disturbance of this equilibrium after a longer or shorter time becomes so great that life ceases. By far the greater number of all diseases furnish examples of this kind. Disease is nothing else but reaction to stimulation. Should a constant stimulus persist and if the development of a new equilibrium of this system is not established, the result is premature death.