On the Nature of Viruses^ Genes and Life* 



WENDELL M. STANLEY 



Director of the Virus Laboratory, University of California, 

 Berkeley, California, U.S.A. 



Recent scientific discoveries, especially in the virus field, are throwing new light 

 on the basic nature of viruses, genes and even life itself. These discoveries are 

 providing evidence for relationships between these three subjects which indicate 

 that one may be dependent upon another to an extent not fully appreciated here- 

 tofore, and hence the time is appropriate for a declaration of the nature of the 

 dependence that may be involved. Too often one works and thinks within too 

 narrow a range and hence fails to recognize the significance of certain facts for 

 other areas. Sometimes the important new ideas and subsequent fundamental 

 discoveries come from the borderHne areas between two weU-established fields 

 of investigation. I trust, therefore, that this discussion will result in the synthesis 

 of new ideas regarding viruses, genes and Ufe and that these ideas in turn will 

 result in the doing of new experiments which may provide the basis for funda- 

 mental discoveries in these fields which are so important to every one of us. 



Now I suppose there is no doubt but that, of the three topics, life is the one 

 that most people would consider to be of the greatest importance. One would 

 think that the nature of life would be easy to define since we are all experiencing 

 it. However, just as Hfe means different things to different people, we find that 

 in reahty it is extremely difficult to define just what we mean by life or by a 

 living agent in its most simple form. There is no difficulty in recognizing an 

 agent as hving or non-Hving so long as we contemplate structures such as man, 

 cats and dogs, or even small organisms such as the bacteria, or, at the other ex- 

 treme, structures such as a piece of iron or glass, an atom of hydrogen or even a 

 molecule of water, sugar or of our blood pigment, haemoglobin. The former are 

 examples of animate or Hving agents whereas the latter are examples of inani- 

 mate or non-living things. But what is the true nature of the difference between 

 a man and a piece of iron, or between a bacterial organism and a molecule of 

 haemoglobin ? The ability to grow or reproduce and to change or mutate have 

 long been regarded as special properties characteristic of living agents. Certainly 

 mankind and bacteria have the abihty to assimilate and metabolize food, respond 

 to external stimuH and to reproduce their kind — properties not shared by bits 

 of iron or by molecules of haemoglobin. Now if viruses had not been discovered, 

 all would have been well. The organisms of the biologist would have ranged from 

 the largest of animals, whales and elephants and the like, all the way down to 



* Adapted from a lecture given before the American Philosophical Society in Phila- 

 delphia, Pa., on April 25, 1957. 



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