The most ancient ancestors of Man, as of all other organisms, were living creatures of the simplest kind imaginable, _organisms without organs_, like the still living Monera. They consisted of simple, homogeneous, structureless and formless little lumps of mucous or albuminous matter (protoplasm), like the still living Protamœba primitiva. (Compare vol. i. p. 186, Fig. 1.) The _form value_ of these most ancient ancestors of man was not even equal to that of a cell, but merely that of a _cytod_ (compare vol. i. p. 347); for, as in the case of all Monera, the little lump of protoplasm did not as yet possess a cell-kernel. The first of these Monera _originated_ in the beginning of the Laurentian period by _spontaneous generation_, or archigony, out of so-called “inorganic combinations,” namely, out of simple combinations of carbon, oxygen, hydrogen, and nitrogen. The assumption of this spontaneous generation, that is, of a mechanical origin of the first organisms from inorganic matter, has been proved in our thirteenth chapter to be a necessary hypothesis. (Compare vol. i. p. 338.) A direct _proof_ of the earlier existence of this most ancient ancestral stage, based upon the fundamental law of biogeny, is possibly still furnished by the circumstance that, according to the assertions of many investigators, in the beginning of the development of the egg, the cell-kernel, or nucleus, disappears, and the egg-cell thus relapses to the lower stage of the cytod (Monerula, p. 124; _relapse_ of the nucleated plastid into a non-nucleated condition). The assumption of this first stage is necessary for most important general reasons. SECOND STAGE: +Amœbæ+. The second ancestral stage of Man, as of all the higher animals and plants, is formed by _a simple cell_, that is, a little piece of protoplasm enclosing a kernel. There still exist large numbers of similar “single-celled organisms.” Among them the common, simple Amœbæ (vol. i. p. 188, Fig. 2) cannot have been essentially different from these progenitors. The _form value_ of every Amœba is essentially the same as that still possessed by the egg of Man, and by the egg of all other animals. (Vol. i. p. 189, Fig. 3.) The naked egg-cells of Sponges, which creep about exactly like Amœbæ, cannot be distinguished from them. The egg-cell of Man, which like that of most other animals is surrounded by a membrane, resembles an enclosed Amœba. The first single-celled animals of this kind arose out of Monera by the differentiation of the inner kernel and the external protoplasm; they lived in the earlier Primordial period. An irrefutable proof that such single-celled primæval animals really existed as the direct ancestors of Man, is furnished according to the fundamental law of biogeny (vol. i. p. 309) by the fact that the human egg is nothing more than a simple cell. (Compare p. 124.) THIRD STAGE: +Synamœbæ+.