CHAPTER HI 



CLASSIFICATION OF LIVING TYPES 



Eeasons for extending the meaning of the word life to include a 

 ■wider class of phenomena — Sciences not divided into water- 

 tight compartments, but their division largely arbitrary — 

 Survival of living proteid— Definition of life — Life-stuff — 

 Manner in which it may have at first arisen — Continuity of 

 organic and inorganic matter — Biogenesis carried to its 

 logical extreme — Haeckel and biogenesis — Cyclic process 

 the test of life in the higher forms of matter — Whether a 

 ceU-waU is necessary in ultra-microscopic germs — Metabolic 

 combination of two opposite processes — How they are 

 effected — Formation of molecular aggregates — Many crys- 

 tals may be fossilised remains of living matter — Classifica- 

 tion should not be between organic and inorganic but 

 between active and inert matter. 



The metliod of classification which we venture to 

 adopt is based upon the idea that simpler modes of 

 life than the amoeba have existed, though they may 

 have long since perished, and that in many properties 

 of matter we can trace the more elementary pro- 

 cesses which have given, and can to some extent 

 again give, occasion to produce them. 



The classification is thus merely to emphasise not 

 only the analogy between such types and the living 

 forms around us like bacteria, but also to lay stress 

 upon the equally striking differences between them. 



