xii Table of Contents 



II. Diflfusion Tension of the Solvent. 

 III. Experimental Demonstration of Osmotic Pressure. 



Chapter ■ VI. Measurement and Calculation of Osmotic 



Pressure .... 35 



I. Measurement of Osmotic Pressure. 



a) Direct Method. 



b) Indirect Methods. 



1. Freezing-point. 



2. Boiling-point. 



3. Vapor Tension. 



II. Calculation of Osmotic Pressure. 



a) Non-electrolytes. 



b) Electrolytes. 



PART II. PHYSIOLOGICAIi CONSIDERATIONS 

 Introduction - - - 47 



Chapter I. Turgidity - 49 



I. Protoplasm and its Limiting Membranes. 

 II. Plasmolysis. 



III. The Permeability of the Protoplasmic Layers. 

 a) Test by the Plasmolytic Method. 



6) Direct Test of Penetrability. 



c) Absorption Test. 



d) Test by Toxicity. 



e ) Test by Accumulation. 



/) Test by Metabolic Processes. 

 g) Outward Permeability. 

 h) Variations in Permeability. 



IV. Action of the Protoplasmic Membrane. 



a) The Filter Theory. 



b) The Solution Theory. 



c ) The Chemical Theory. 

 •J V. The Nature of the Osmotically Active Solutes. 



VI. The Maintenance of Turgidity in Spite of Permeability to 

 Certain Solutes. 

 The Relation of Turgidity to Vital Activity. 



a) The Retention of Form. 



b) Mechanical Support. 



c) Grovpth. 



d) Curvature. 



e) Work. 

 Summary of the Chapter. 



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