The physical properties of cytoplasm

1. 1. A magnetic method is described for the study of the consistency of the protoplasm of living cells in tissue cultures. 2. 2. Such protoplasm is not purely viscous, but has elastic properties. 3. 3. The order of magnitude of the modulus of rigidity is 10 2 dynes/cm 2 . 4. 4. There is evidence of thixotropic behaviour. 5. 5. The bearing of these results on current theories of protoplasmic structure is discussed.