[Disturbances of Free Water and Electrolyte Metabolism: Three large groups are differentiated]

1. Disturbances of free water which are related to the whole body water and are always coupled with changes in the osmolality of the internal environment and also of the interior of the cells. 2. Isotonic changes of the volume of the extracellular fluid- edema or extracellular dehydration. The latter is always coupled with a hypovolemia and with a danger to the circulation which may end in shock. There is also a cumulative loss of potassium as a result of the dehydration reaction. 3. Disturbances of the intracellular water metabolism which are associated with disturbances of the potassium metabolism. These may have consequences for the function of striated and smooth muscles, for the function of the nerves and various enzyme systems.