“In this manner we can conceive that the hiatus between non-living and living things can be bridged over, and there awakens in our minds the conception of a kind of spontaneous production of life of a different order from the old. The territory of this spontaneous generation of life lies not at the level of bacteria, or animalculæ, springing forth into life from dead organic matter, but at a level of life lying deeper than anything the microscope can reveal, and possessing a lower unit than the living cell, as we form our concept of it from the tissues of higher animals and plants. “In the future, the stage at which colloids begin to be able to deal with external energy forms, such as light, and build up in chemical complexity, will yield a new unit of life opening a vista of possibilities as magnificent as that which the establishment of the cell as a unit gave, with the development of the microscope, about a century ago.” (“Origin and Nature of Life,” pp. 188-190.) Having heard out a rhapsody of this sort, one may be pardoned a little impatience at such a travesty on science. Again we have the appeal from realities to fancies, from the seen to unseen. Moore sees no reason to doubt and is therefore quite sure that an unverified occurrence is taking place “at a level of life lying deeper than anything the microscope can reveal.” The unknown is a veritable paradise for irresponsible speculation and phantasy. It is well, however, to keep one’s feet on the _terra firma_ of ascertained facts and to make one’s ignorance a motive for caution rather than an incentive to reckless dogmatizing.