NIELS BOHR 3 



ot the atoms ol Avhich they are composed and the configuration in 

 which these atoms are bound together. 



The discoveries in recent years of the specific molecular structures 

 carrying genetic iniormation, and the increasing insight into the 

 processes by which this iniormation is transferred, have opened quite 

 new prospects for the gradual elucidation of biological regularities 

 on the basis of well-established principles of chemical kinetics. In 

 particular, the almost unlimited possibilities of probing our metabolic 

 transformations lend support to the view that the formation and 

 regeneration of the structural constituents of the organisms are to 

 be regarded as processes of not immediately reversible character, 

 which at any step secure the greatest possible stability under the 

 conditions maintained by nutrition and respiration. 



Thus, there appears to be no reason to expect any inherent limi- 

 tation of the application of elementary physical and chemical con- 

 cepts to the analysis of biological phenomena. Yet, the characteristic 

 properties of living organisms, which have resulted from the whole 

 history of organic evolution, reveal potentialities of immensely com- 

 plicated material systems, which have no parallel in the comparatively 

 simple phenomena studied under reproducible experimental condi- 

 tions. It is on this background that notions referring to the behavior 

 of organisms as entities, and apparently contrasting with the account 

 of the properties of inanimate matter, have found fruitful application 

 in biology. 



Even though we are here concerned with typical complementary 

 relationships as regards the use of appropriate terminology, it must 

 be stressed that the argumentation differs in essential aspects from 

 that concerning exhaustive objective description in quantum physics. 

 Indeed, the distinction demanded by this description between measur- 

 ing apparatus and object under investigation, which implies mutual 

 exclusion of the strict application of space-time coordination and 

 energy-momentum conservation laws in the account of individual 

 quantum processes, is already taken into account in the use of chemical 

 kinetics and thermodynamics. Thus, the dual approach in biology 

 does not seem to be conditioned by an interference with the proper- 

 ties of the specific molecular structures, inherently involved in their 

 identification, but is rather required by the practically inexhaustible 

 potentialities of living organisms entailed by the immense complexity 

 of their constitution and functions. 



