112 WHAT IS LIFE 



for its work ; to set itself in motion and keep itself 

 going; to repair itself, within certain limits, the 

 defect that may arise ; and above all, by the fact 

 that it constructs itself. In short, an organism 

 in contradistinction to the dead machine is a 

 living machine, one that does not depend upon 

 external impulses for its movements, one that 

 regulates its own course, and continues going as 

 long as the environment will allow only through 

 the hostility of this or through irreparable mis- 

 fortune is it brought to a halt." 



The power to repair itself here is a thing not 

 met with or begun to be suggested in any machine. 

 Professor Hartog l very acutely points this out in 

 connection with the so-called automatic machines. 

 He says, " In its original use ' automatism ' desig- 

 nates the continuous sequence and combination of 

 actions, without external interference, performed 

 by complex machines designed and made for specific 

 ends by intelligent beings : thus we speak correctly 

 of ' automatic ball bearings ' that tighten themselves 

 when they become loose ; but even these cannot 

 take up fresh steel and re-deposit it, either to 

 replace the worn parts or to strengthen a tube that 

 is bending under a stress." 



The difference between the living organism and 

 a machine has been very carefully considered by 

 1 Op. cit., p. 12. 



