CONTENTS xix 



CHAPTER XXIX 



PAGE 



THE BEHAVIOUR OF PLANTS IN MASSES .... 313 

 Action on a plant by the toxin formed by itself; pot experi- 

 ments on plants with and without root interference; growth 

 in a limited supply of soil; branch interference; different 

 numbers of plants grown in the same amount of soil ; evidence 

 of toxic action when the plants are dissimilar in age ; importance 

 of uniform germination in a seed-bed; inadvisability of filling 

 up gaps in a plantation; difference in magnitude of the toxic 

 action with mustard and wheat ; behaviour of the outside rows 

 in a plantation ; impossibility of explaining this by the extra 

 food-supply. 



CHAPTER XXX 



FLOCCULATION . . . ; . . 323 



Characteristics ; Brownian motion arrested and size of particles 

 increased on flocculation ; explanations offered ; reason of the 

 formation of floes; action of alkalis; the liming of fields; 

 adsorption compounds; effect of rainfall on the distribution 

 of clay-particles in the soil; action of frost on clay. 



CHAPTER XXXI 



ODDS AND ENDS ......... 329 



Comparative bearing of apples on crab and paradise stocks. 

 Influence of the stock on the growth of trees ; relative merits 

 of budding and grafting; influence of the scion on the stock; 

 the question as to what characteristics of the scion are repro- 

 duced in subsequent growth from it ; the possible deterioration 

 of varieties by continued re- working on to fresh root-stocks. 

 Relative behaviour of different varieties of strawberries under 

 different conditions; futility of variety testing. Continuous 

 cropping with strawberries. Behaviour of late and early 

 strawberry runners. Germination of apple seeds from large 

 and small fruits, and from cells containing different numbers 

 of seeds. Potatoes ; early and late planting ; planting different- 

 sized sets; change of seed. A disease of plum trees. 



