Page:The Harveian oration (electronic resource) - Royal College of Physicians, 1881 (IA b20411911).pdf/34

 living organisms capable of rapid reproduction? I confess that I have always ranged myself with those who believed that the newly-developed organism commenced in the same germinal form which afterwards served for its propagation. Let me not be misunderstood. There is nothing irrational in the conception that these minute organisms may either produce fully-matured spores or germs, or may be propagated by fissure and subdivision. The word germ "may," for the present, be fairly applied to the immature object of either kind, which afterwards develops into a living being.

All the hypotheses which have been suggested in connection with the propagation of this lower stratum of life, revealed, as it has been, within a comparatively recent period by the more perfect optical instruments of the present day, have gone on the assumption that their development demands the presence of some force different from that which we find in constant operation; and the further question opens a wide field of controversy—viz., What is that force? The minutest of these creatures are invisible to the highest powers of the microscope in the solution to-day—to-morrow they are swarming in hundreds or thousands. How is this? Has any other change in our solution taken place, and is that change constant? It was very easy to confute Mr. Cross, who put forward the suggestion that electricity had the