The individual organs follow the same pattern as the whole organism, i.e. they have their period of growth, of stationary, maximum activity and then of aging decline.

; Jespersen O. Leipzig. Energetische Grundlagen der Kulturwissenschaft (1st ed.

Ostwald Jacobus Henricus van 't Hoff and Svante Arrhenius are usually credited with being the modern founders of the field of physical chemistry. He received the Nobel Prize in Chemistry in 1909 for his work on catalysis chemical equilibria and reaction velocities.