CONTENTS. 



PA.QE 



Historical 3 



Experimental Methods 10 



Determination of Acidity 10 



Determination of Respiration by the Pettenkofer Method 13 



Methods in Gas-interchange Determinations 15 



General Methods of Procedure and Precautions 20 



Acidity Determinations 25 



Periodicity in Acidity 25 



Effect of Light on Acidity 29 



Effect of Temperature on Acidity 30 



Effect of Injury on Acidity 34 



Miscellaneous 35 



Experimental Data on Acidity Determinations, Tables 7 to 25 37 



Evolution of Carbon Dioxide as determined by the Pettenkofer Method 47 



Normal Respiration 47 



Wound Respiration 52 



Diurnal Periodicity in relation to Temperature 53 



Experimental Data of Determinations with Pettenkofer Apparatus, Tables 28 to 41 .. 55 



Gas Interchange 63 



General Considerations 63 



Quantities in Gas Interchange 66 



Temperature Effect 68 



Gas Interchange Ratio and Acidity 71 



Gas Ratio and Rate of Gas Interchange 73 



Acidity and Rate of Gas Interchange 75 



Pure Juice Acidity and Rate of Gas Interchange 77 



Certain Anomalous Cases 78 



Relation of Gas Ratio to Course of Acidity 79 



Evolution of Carbon Dioxide in Diffuse Light and Direct Sunlight 82 



Evolution of Carbon Dioxide in the Absence of Oxygen 84 



Increased Oxygen Supply and Gas Interchange 85 



Gas Interchange over Long Periods 86 



Experimental Data of Gas Interchange Determinations, Tables 53 to 67 87 



Summary and Conclusions 100 



1 



