LIFE, CARBON'S OUTSTANDING PROPERTY 77 



only those which have that distinctive life quality, the ability 

 to grow and to propagate itself in an environment different 

 from itself. This is indeed a rare property. Such mate- 

 rials as sugar or salt will, in general, not show it. Nor can 

 any crystals be classified as living if they grow only in their 

 own saturated solution. The material must have the power 

 of transforming nutrient material, as the green chlorophyl 

 of plants transforms the gaseous dilute carbon of the air 

 into plant material. But even this is not sufficient ; chloro- 

 phyl is a part of the living plant, yet it is not a living thing 

 itself, since it can only transform the gaseous carbon dioxide 

 into plant material, not reproduce itself. 



Evidently the virus material does have the power of 

 transforming its food material. It is active material, a 

 so-called enzyme but in this case the product of the trans- 

 formation is the virus material itself. Thus it propagates 

 itself as long as there is available food material like the 

 tobacco leaves on which the tobacco mosaic "feeds." And 

 yet the virus is a chemically pure substance in the same 

 sense as pure cane sugar. How is this possible? 



Chemically pure substances can only reproduce by en- 

 zyme action. The virus does just this. By its enzymatic 

 action it initiates in its surroundings a chemical reaction 

 which results in the formation of identical viruses, which are 

 also enzymes of the same type. There is positively no 

 reason to deny that a single molecule has the essential 

 properties of a living organism, if it is an enzyme which has 

 the power of producing in a naturally occurring environ- 

 ment chemical reactions that lead to its own multiplication. 

 This means that such an enzyme propagates itself in the 

 same manner as a living organism. In this sense life is a 

 property of matter, but only of a highly specialized kind of 

 matter. 



Is it possible to make this kind of matter artificially? 

 Organic chemistry in its present stage of development has 

 not yet advanced that far. It has not even developed to 



