BIOLOGICAL ORDER 



that an organism reproduces true to type is therefore true 

 only statistically. Heredity and variation are combined in the 

 living system. The structure of the organism includes its past, its 

 historical experience. What is the molecular basis of hereditary 

 variation? 



An organism is an integrated unit of structure and functions. In 

 an organism, all molecules have to work in harmony. Each molecule 

 has to know what the other molecules are doing. Each molecule 

 must be able to receive messages and must be disciplined enough to 

 obey orders. How has the organism solved the problem of inter- 

 molecular communication? 



An organism rarely lives in a constant environment. When the 

 environment varies, the organism has to cope with the variations. 

 As a matter of fact, the constitutive, dependent parts of the organ- 

 ism, its molecules, are submitted to a dual action: they are controlled 

 by the genetic material, which is responsible for heredity and evolu- 

 tion, and at the same time they are subject to the action of the 

 environment. And one would like to know something about the 

 interaction of hereditary and environmental factors, about the way 

 the organism as a whole decides what it has to do when faced with 

 a given situation. 



Everyone knows that things are not always as they should be. 

 This is in a sense fortunate, for otherwise life would be boring; I 

 mean, of course, molecular life. Freedom is essential for the develop- 

 ment and blooming of the human being. But as part of an organized 

 society the human being has to accept a certain number of restraints. 

 This is true for molecules. When a molecule develops a strong 

 personality and refuses to submit herself to the common rule, the 

 organism is dangerously threatened. In an ideal molecular society, 

 each molecule works for the community, that is, for the organism. 

 This is what happens normally. Yet a molecule sometimes decides 

 to get rid of the shackles of co-ordination and to work for its own 

 profit. As a result, all sorts of molecular diseases are produced. 

 Molecular freedom is a catastrophe. Molecular diseases, of which 

 viral diseases are only one aspect, pose a number of problems that 

 we shall have to discuss. 



[8] 



