The Conditions of Life and Death. 85 



of local life which remain in parts of an organism, e.g. 

 the turtle's heart, which may beat long after the con- 

 tinued life of the entire animal is out of the question, 

 indeed after the bulk of the creature has been made into 

 soup. 



In short, here again we face the suggestion that the 

 state of life and the state of death are but the extremes 

 of a long series. 



From Treviranus to Verworn, from Claude Bernard 

 to Le Dantec, biologists have endeavoured to state the 

 characteristics of living organisms; but a characteris . 

 historical summary is not yet justified, since tics of Living 

 so little progress has been made. It is not Or e anisms - 

 even possible to say that we have got rid of mysticism. 

 We have become more concrete than Linnaeus was 

 when he penned his famous aphorism " Lapides 

 crescunt; vegetabilia crescunt et vivunt; animalia cres- 

 cunt, vivunt, et sentiunt"; and we have probably be- 

 come more aware of our ignorance. 



It is not, therefore, with any confidence that we 

 here emphasize three characteristics which distinguish 

 the living from the not-living. 



(1) The first is the power of organic growth, the 

 power of repairing loss and increasing size at the 

 expense of material more or less different from that 

 which forms the organism. The crystal grows, but it 

 grows only out of material similar to itself, while the 

 grass grows at the expense of air, water, and salts, and 

 the horse at the expense of the grass. 



(2) The living creature, as long as it is actively alive, 

 is interacting with its environment; it is the subject of 

 more or less continuous chemical changes, some of 

 which are direct reactions to the outside world, while 

 others are only indirect reactions; yet, in spite of this 

 flux and unrest, the organism remains for variable 

 periods much the same, it retains its integrity or unity 

 of character. 



(3) An organism is often compared to an engine, and 

 the two are alike in being material systems adapted for 

 the transformation of matter and energy from one form 

 to another. But there are differences. Not only is 



