LIVING PLANTS 



IV. Mimosa : A Typical Sensitive Plant, D. T. Mac- 



DOUGAL 47 



I'ses of movement — Power of movement— Characteristics 

 of mimosa — Organization — Day position of leaves — Night 

 position of Leaves — Reaction to shock, etc. — Transmis- 

 sion of stimuli — Repetition of stimuli — Methods of trans- 

 mission — Purpose of reaction to shock. 



V. Universality of Consciousness and Pain, J, C. 



Arthur 63 



Unity in nature — Superstition of the mandrake — Can 

 a mandrake feel — Meaning of consciousness — Examples 

 of consciousness — Definition of terms — General irritabil- 

 ity — Welfare of the organism — Adaptive movements im- 

 ply consciousness — Pain a factor in evolution — Action of 

 plants difficult to interpret — Plants not degenerates. 



VI. How Cold Affects Plants, D.T.MacDougal. 85 



Varying reaction to cold — Appearance of frozen plants — 

 Ice in the tissues — Relation of cell to cold— Relation of 

 organism to cold — Death above freezing point — Adapta- 

 tions against cold. 



VII. Two Opposing Factors of Increase, J. C. Ar- 



thur 99 



Two sides to plants — Nutrition and development — Effect 

 of soil fertility — Provision for perpetuity — Size of seeds — 

 Early growth — Final yield — Superiority of large seeds — 

 Vegetative and fruiting parts compared — External and 

 internal factors. 



VIII. Chlorophyll and Growth, D.T. MacDougal. 121 



Historical — Methods of experimentation — Growth in the 

 absence of carbon dioxide — Effect of darkness — Total re- 

 sults w^ith Arisaema — Results with Calla — Results with 

 Zea — Results with Phcenix — Ordinary course of growth 

 — Growth with insufficient nutrition — Conclusions 



IX. Leaves in Spring, Summer, and Autumn, D. T. 



MacDougal 145 



Importance of chlorophyll — Properties of chlorophyll — 

 Varying tints — Synthesis of food — Acquisition of chloro- 

 phyll — Autumnal leaf-fall — Withdrawal of leaf-substance 

 — Color as a protecting screen — Separation layer — Ever- 

 green leaves. 



