The theory of van der Waals forces has now developed to a stage where it constitutes a powerful tool in theoretical investigations of many biological systems. In this review we shall consider both the theoretical and conceptual aspects of these forces with the emphasis on the way they may be involved in various biological processes.

Few fields of biochemistry have seen such widespread applications of physical theories and techniques as that of biological oxidation. There are obvious reasons for this. Oxidation-reduction reactions form the foundations of bioenergetics, an area which can only be understood in terms of thermodynamic theory. Most components of the mitochondrial respiratory chain contain transition metals, and these elements and their chemical environment can often be studied by modern spectroscopic methods, such as electron-paramagnetic resonance (EPR). The relation between spectroscopic properties and chemical structure of metallo-proteins, e.g. haem proteins, represents one of the few branches of present-day biochemistry to which quantum mechanical calculations can profitably be applied (see, for example, Zerner, Gouterman & Kobayashi, 1966).

This review takes the regulation of breathing in man as an example of a highly developed and much studied control system in higher mammals.

It is well known that excited states may be generated chemically in biological systems as evidencex and by the phenomenon of bioluminescence and it is natural to suspect that they may also be generated and used in dark processes (Szent-Györgyi, 1941; Steele, 1963; Cilento, 1965; White & Wei, 1970; White et al. 1971). Förster (1967) has pointed out that electronic excitation and subsequent transfer processes may occur in biological dark systems despite the fact that the energy available from enzymic processes is too low to excite aromatic amino acids and other biochemical structures. Hastings (1968) suggests that in some organisms light emission is just an alternative to the formation of an active species.

In the article ‘Molecular interactions and structure as analysed by fluorescence relaxation spectroscopy’ by Rudolf Rigler and Måns Ehrenberg, which appeared in Quarterly Reviews of Biophysics 6, 2 (1973), pp. 139–199, printing errors occurred:

P. 145, 1.8:should read

P. 153, 1.20: … coefficient in some cases… should read …coefficient and in some cases…

P. 159, 1.13: …, φ2(λ′) should read …, φλ(λ′)…

P. 190, 1.4: … as well as the signal-to-noise ratio,… should read … as well as of the signal-to-noise ratio,…