98 



Plant Physiology 



occur during a cool afternoon or evening of a warm day ; 

 and quite commonly in the cool early morning after a hot day 



[Photoyraph by Russell and Harding.} 



FIG. 30. Destruction of cabbages by Pseudomonas campestris, a germ 



entering through the water-pores. 



which has served to heat up the soil to a considerable depth. 



The continuous water connection between the tissues 



and the external atmosphere established through guttatioii 



