CONDUCTIVITY AS A MEASURE OF VITALITY AND DEATH

The conductance of Laminaria, Saccharomyces, Bacillus coli and Bacillus butyricus, Chlorella, and of red blood cells has been studied by the writer's method, and Laminaria by that of Osterhout. For the material studied it has been found that: 1. The conductance of living tissue is closely proportionate to, and determined by that of the surrounding fluid with which it is apparently in equilibrium. Changes in the conductance of the fluid are quickly followed by compensatory changes in that of the tissue. 2. A quantity is defined which is independent of the conductivity of the fluid bathing the tissues. This is called the "net conductance." 3. All the tissues studied, even when dead, offer a resistance to the passage of current greater than that of the surrounding solution. Exceptions which occur under certain conditions will be discussed in a later paper. 4. In view of the wide variety of material studied it seems admissible, in the absence of any evidence to the contrary, to suppose that these conclusions are generally applicable.