CONTENTS 



X. The Significance of Color, D.T. MacDougal..165 



Early views — Sprengel's discoveries — Ecological consider- 

 ations — Enumeration of colors — Chlorophyll — Etiolin — 

 The lipochromes — Anthocyans— Relation of anthocyan 

 to light — The screen theory — Promotion of metabolism 

 — Promotion of transpiration — Red seaweeds — Mark- 

 ings not due to color — Silvery areas — Velvety surfaces 

 — Conclusions. 



XI. The Right to Live, J. C. Arthur 193 



Aggressiveness of plants — Likeness of plants and animals 

 — Possible rate of increase — Weeds as examples — Prolifi- 

 cacy of other plants — Illustrative similes — A world of 

 strife — Destruction of life for a dinner — Natural right to 

 food — Logic of good fortune — Object of living — Death not 

 essential to life — Plants are born to live — Right to life 

 should be respected. 



XII. Distinction between Plants and Animals, 



J. C. Arthur 209 



Learned vagaries — Ancient opinions — Modern opinions — 

 An intermediate kingdom— Blending of the two kingdoms- 

 Characters from structure and function — Various physio- 

 logical distinctions — The most universal structures — 

 Characters to be taken from the active organism — Repro- 

 ductive states to be ignored — Animals and plants defined 

 — Chemical features of cell walls — Physical features of 

 cell walls — The test applied. 



XIII. Index to Plant Names 229 



