The distinction between the old and the new formulations consisting in the incorporation of the concept of the rate of chemical reactions is so great that it immediately asserted itself in the objective development of catalysis.

The well-known fact that the form of a specific substance, e.g. water, and hence its properties can alter without a change in composition was disposed of by the formal view that a physical, not a chemical, process was involved.

We know from biology that new forms of organisms simulate their primitive form as closely as possible at first, even though obliged to exist under changed internal and external conditions.

In the first quarter of the nineteenth century the experimental proof for the interdependence of the composition and properties of chemical compounds resulted in the theory that they are mutually related, so that like composition governs like properties, and conversely.

The distinction between the old and the new formulations consisting in the incorporation of the concept of the rate of chemical reactions is so great that it immediately asserted itself in the objective development of catalysis.

Nowadays, however, we recognize that simultaneously with the typical case of a chemical reaction a typical case of catalytic effect had been studied which constitutes a limiting case.

My only supporter and comrade-in-arms was Georg Helm, who had endeavored to formulate an energetic conception of science before me and had presented his results in a treatise [Die Lehre von der Energie] exhibiting great independence of thought. But we were separated by his aversion to a realistic conception of energy. Consequently, each of us considered the other only a half ally, toward whom an attitude of caution was necessary.