The difference of attitude is clearly shown if we consider from the two points of view a complicated organ-system such as the central nervous system. The atomist sees in this a mere aggregate of cells or at the most of groups of cells. "The morphologist," on the other hand, "sees in the central nervous system a _proximate_ element in the composition of the body--a primitive organ. From this point of view he apprehends and judges its morphological relations with, in the first place, the other co-ordinated primitive organs in the system as a whole; in all this the cells remain in the background, and have nothing to do directly with the determination of these morphological relations" (p. 6). Within the nervous system there are separate organs which stand to one another in a definite morphological and functional relationship. These organs are, it is true, composed of cells; but between the form and connections of these organs and the cells which compose them there is no direct and necessary relation (p. 6). It is true that the cell is the ultimate element of organic form, and that all development takes place by multiplication and form-change of cells. Yet is the cell in all this not independent of the unity of the developing embryo, and what the cells produce, they produce, so to speak, not of their own free will, nor by chance, but under the guiding influence of the unity of the whole, and in a certain measure as its agents (p. 7). The atomists will not admit the truth of this; they see in development nothing more than a process of the form-change and multiplication of cells. The full meaning of development escapes them, for they take no cognisance of the increasing complexity of the embryo, of the separating-out of tissues, of the moulding of organs, of the harmonious adaptation and adjustment of the parts to form a working whole. In general, the fault of the atomists is that they do not respect the limits which Nature herself has prescribed to the process of logical analysis and disintegration of the organism; they do not recognise the existence of natural and rational units or unities; they forget the one great principle of rational analysis, "that, by universally valid, inductive, logical method, natural objects must in all cases be accepted and dealt with in the combination and concatenation in which they are given" (p. 10).