no value to the cell. It would be quite erroneous if we were to consider any substance—for instance, albumen—as the paramount life substance. A single ion can in certain cases decide the life or death of a cell. An aggregation of molecules may combine to form a powerful complex—a colloid—and by means of its properties dominate the whole function of a cell. The structure and configuration of the separate compounds, and of the separate units of the cell are of the greatest importance for its individuality. To this we must add, and as partly conditioned by the above, their structure and configuration in the physical sense. A. separation of the chemical and physical properties of the cellular units is impossible, since they constitute mutually the conditions of life for the cell. They stamp it with its own character.
Substances, which may be indifferent products for one kind of cell, may be injurious to another kind. Each cell produces secretions of its own, in the formation of which many intermediate stages are passed through. If the whole transformation into substances that will be in harmony with the plasma be performed inside the cell, then any by-products that may appear, even though they be not indifferent in regard to other cells, will display no injurious activity in the organism as a whole. If, however, such insufficiently transformed substances penetrate into the general
