Later observers concluded that the green color of certain infusorians, of the common fresh water hydra and of the fresh water sponge, was due to the same pigment, but little more attention was paid to the subject until 1870, when Ray Lankester applied the spectroscope to its investigation.
For that matter, when Aristotle grouped animals with backbones as blood relations, he began the sort of classification which, when extended by Darwin to monkeys and men, so shocked my uncle. In the meantime the microscope had been invented. It revealed a new world of hitherto invisible creatures called Infusorians, as common water was found to be an infusion of them.
All about him, as the young man moved through the water, there were millions of tiny organisms that would betray his presence, as they had the shark's, at the first ripple. These minute infusorians would glow with the pale gleam of phosphorescence if the water were ruffled. Therefore, he had to swim carefully and slowly, when each second his nerves cried out for rapid, panic-stricken action.
But by and by there arose sectarian quarrels with other backwoods folk who also wished to worship God in Kentucky, and hot personal disputes among the members as is the eternal law. So that the church grew as grow infusorians and certain worms, by fissure, by periodical splittings and breakings to pieces, each spontaneous division becoming a new organism.