Note 7 — Chapter I · THE PROBLEM STATED.

I am often reminded of the surprising movements of particles of carbonate of lime in water which my friend Professor Preyer showed me during a visit to Bonn. He had removed one of the concretions, usually found in connection with nerves along the spine of old frogs, and crushed it in water; under the microscope the seeming spontaneity and variety of the movements of the particles was such that had we not known their origin we should certainly have attributed them to vitality: no infusoria could have moved with more seeming spontaneity. It is hardly physiological to conclude that because fragments of tissue manifest ambœbiform movements therefore they are alive (Stricker, art. Die Zelle in his Handbuch der Lehre von den Geweben, 1868, p. 7), or that the heart removed from the body is alive because it still beats. Lieberkühn, Ueber Bewegungserschsinungen der Zellen, 1870, pp. 357–359, cites examples of such movements in undeniably dead substances. For Life, we demand not only Movement, but Functional Activity.