In fact, the very notion of a chemical synthesis of living matter is founded on a misconception. It would, indeed, be rash to set limits to the chemist’s power of synthesizing organic compounds, but living protoplasm is not a single chemical compound. Rather it is a complex system of compounds, enzymes and organelles, coördinated and integrated into an organized whole by a persistent principle of unity and finality. Organic life, to say nothing at all of its unique dynamics, is a morphological as well as a chemical problem; and, while it is conceivable that the chemist might synthesize all the compounds found in dead protoplasm, to reproduce a single detail of the ultramicroscopic structure of a living cell lies wholly beyond his power and province. “Long ago,” says Wilson (in the already quoted address on the “Physical Basis of Life”), “it became perfectly plain that what we call protoplasm is not chemically a single substance. It is a mixture of many substances, a mixture in high degree complex, the seat of varied and incessant transformations, yet one which somehow holds fast for countless generations to its own specific type. The evidence from every source demonstrates that the cell is a complex organism, a microcosm, a living system.” (_Science_, March 9, 1923, p. 278.) With the chemist, analysis must precede synthesis, and it is only after a structural formula has been determined by means of quantitative analysis supplemented by analogy and comparison, that a given compound can be successfully synthesized. But living protoplasm and its structures elude such analysis. Intravitous staining is inadequate even as a means of qualitative analysis, and tests of a more drastic nature destroy the life and organization, which they seek to analyze. “With one span,” says Amé Pictet, Professor of Chemistry at the University of Geneva, “we will now bridge the entire distance separating the first products of plant assimilation from its final product, namely, living matter. And it should be understood at the outset that I employ this term ‘living matter’ only as an abbreviation, and to avoid long circumlocution. You should not, in reality, attribute life to matter itself; it has not, it cannot have both living molecules and dead molecules. Life requires an organization, which is that of cellular structure, but it remains, in contradistinction to it, outside the domain of strict chemistry. It is none the less true that the content of a living cell must differ in its chemical nature from the content of a dead cell. It is entirely from this point of view that the phenomenon of life pertains to my subject.... A living cell, both in its chemical composition and in its morphological structure, is an organism of extraordinary complexity. The protoplasm that it incloses is a mixture of very diverse substances. But if there be set aside on the one hand those substances which are in the process of assimilation and on the