230 J. E. Lovelock 



which active synthesis maintains the cell at a constant com- 

 position in spite of the dispersion and disorientation of its 

 substance by random molecular movement. 



It is possible to demonstrate physically that the senescence 

 of a cell, so constructed, is inevitable. Until sufficient inform- 

 ation is available to define the life expectation of the red cell 

 on the basis of a particular physical structure, the interpreta- 

 tion of its senescence in terms of physical dissolution remains 

 speculative. In the subject of senescence, as in astronomy, 

 the lack of essential facts is not usually a serious objec- 

 tion to the discussion of a theory. This precedent, and also 

 because further experiments are suggested by the theory just 

 outlined, seems to justify the discussion that follows. 



It is at first sight perhaps surprising that a model cell, 

 which is supplied with unlimited quantitites of energy and 

 which has the means to repair damage suffered as a result of 

 wear and tear, should be subject to inevitable dissolution. 

 There are several ways of formulating this problem in physical 

 terms, but the simplest of these makes use of "information 

 theory" (Shannon and Weaver, 1949). Information theory is 

 primarily concerned with the conveyance of messages. It is 

 well established, in both the theory and practice of this subject, 

 that it is impossible to convey information without some loss 

 or distortion taking place, and this is entirely attributable to 

 the universal tendency for disorganization to occur. Or in 

 other words, to compose a message, something which is dis- 

 tributed at random must be organized and this organization 

 increases its content of energy. The normal and inevitable 

 degradation of this energy with the passage of time results in 

 an equivalent degradation of its content of information. 



In order to preserve its identity in the face of wear and tear, 

 a living cell must possess at its formation a considerable 

 quantity of information to direct the course of its repair 

 functions. Whatever part of the cell possesses this information 

 is itself exposed to the destructive effects of random molecular 

 movement and must eventually become too blurred to func- 

 tion. Admittedly this approach is open to the criticism that it 



