The worst manifestations of exhaustion were successfully cured by a long period of rest but it was immediately apparent to me that I had lost once and for all my former capacity for carrying out experimental work until physically tired.

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.

Science is one land, having the ability to accommodate even more people, as more residents gather in it; it is a treasure that is the greater the more it is shared. Because of that, each of us can do his work in his own way, and the common ground does not mean conformity.

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.

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.

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 development of a rational view of the nature of catalysis was thus absolutely dependent on the creation of the concept of the rate of chemical reaction.