FOREWORD 



By Proflssor C. H. Waddington, Institute of Animal Genetics, University of 



Edinburgh. 



Biology today is entering on to a period of altogether exceptional growth and 

 advance. This is, one may say, its second flowering. The first was the period 

 of the Darwinian synthesis, when the theory of evolution provided for the first 

 time a theoretical framework in which the whole range of living organisms 

 could be seen as interconnected in a manner open to man's comprehension. 

 The initial success of Darwin in establishing the theory of natural selection was 

 followed by an efll^orescence of phylogenetic studies, combined, eventually, 

 with the development of the scientific discipline — classical Mendelian genetics 

 — which was most clearly necessary to complete the edifice of theory which he 

 had erected. Meanwhile, the more down-to-earth, workaday sciences of 

 physiology and metabolic biochemistry, of supreme practical importance for 

 our ability to tinker with, tune up and keep in trim our only too unreliable 

 bodily mechanisms, with their buih-in obsolescence, also made progress which 

 was spectacular in its effect on the span and pleasantness of man's life, but 

 which remained, dare one say, rather a technological achievement than a 

 contribution to man's view of his situation within the universe. 



The last few years have seen — and perhaps the next few decades will con- 

 tinue to see— the first real fusion between the grand biological theories which 

 cast their gaze over the whole realm of living things, and the metabolic biology 

 which comes down to cases and asks, and is sometimes able to tell us, how such- 

 and-such particular biological properties operate. This new phase of bio- 

 logical understanding has arisen in the first place from a decision to study 

 living material in the simplest forms in which it occurs. Geneticists have 

 studied, not only mice and Drosophila, but also viruses and bacteria. Bio- 

 chemists and biophysicists have gone beyond the study of such relatively com- 

 plex parts of the living machine as muscle and nerve to the basic elementary 

 compounds — proteins and nucleic acids — on which the character of living 

 things depends. And in the last few years we have seen the almost explosive 

 development of a Fundamental Biology — often known by the somewhat un- 

 happy name of Molecular Biology — since what material thing is not mole- 

 cular? — which almost rivals Fundamental Particle Physics in its precision and 

 its penetration to the depths of the phenomena with which it is concerned. 



It is very necessary for biologists to remember that the great advances of 

 analytical physics in the theories of quanta and fundamental particles have not 

 only thrown new light on the minute world of the interior of the atom and its 

 nucleus, but have been used to deepen our understanding of the much larger 

 phenomena of the solid state and even the colossal events dealt with by 

 astrophysics ; and they have also been supplemented by theories, such as ther- 

 modynamics and general relativity, which deal with complexes envisaged as 



