Professor O'Connor found that, in like manner, bacteria, of all kinds, were devoured by minuter forms of life. Recovery from sickness meant that the microbes were destroyed by their natural enemies before they had time to take possession of the entire system; death resulted where the vital powers could not hold out until the balance of nature was thus re-established. He found, therefore, that the remedy for disease was to take some of the culture-infusion in which malignant bacteria had just perished, and inject it into the veins of the sick man. This was like stocking a rat-infested barn with weasels. The invisible, but greedy swarms of bacilli penetrated every part of the body in search of their prey, and the man recovered his health. Where an epidemic threatened, the whole community was to be thus inoculated, and then, when a wandering microbe found lodgment in a human system, it would be pounced upon and devoured before it could reproduce its kind. He even argued that old age was largely due to bacteria; and that perpetual youth would be possible if a germicide could be found that would reach every fiber of the body, and destroy the swarming life-forms which especially attacked the vital forces of the aged. And then he referred to a new invention by a California scientist, named Henry Myers, whereby telephonic communication had been curiously instituted with intelligences all around us--not spirits or ghosts, but forms of life like our own, but which our senses had hitherto not been able to perceive. They were new forms of matter, but of an extreme tenuity of substance; and with intellects much like our own, though scarcely of so high or powerful an order. It was suggested by the preacher that these shadowy earth-beings had probably given rise to many of the Old-World beliefs as to ghosts, spirits, fairies, goblins, angels and demons. The field in this direction, he said, had been just opened, and it was difficult to tell how far the diversity and multiplicity of creation extended. He said it was remarkable that our ancestors had not foreseen these revelations, for they knew that there were sound-waves both above and below the register of our hearing; and light-waves of which our eyes were able to take no cognizance; and therefore it followed, _a priori_, that nature might possess an infinite number of forms of life which our senses were not fitted to perceive. For instance, he added, there might be right here, in this very hall, the houses and work-shops and markets of a multitude of beings, who swarmed about us, but of such tenuity that they passed through our substance, and we through theirs, without the slightest disturbance of their continuity. All that we knew of Nature taught us that she was tireless in the prodigality of her creative force, and boundless in the diversity of her workmanship; and we now knew that what the ancients called spirit was simply an attenuated condition of matter.