228 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



slight frost, these tender cells are seriously injured, and the result of a 

 severe frost may be easily imagined. In a canker spot on wood which 

 has passed through some winters, e.g. on three-years-old wood, most of 



Fk;. 35.— Parasitic Canker of Blackbkkky. 



the parenchyma cells are killed, few points of new growth are visible, 

 and the fundus has entirely disappeared, nor are the reddish-brown spots 

 surrounding the cankerous growth present. This is the result of frost, 

 which gives the final blow to the plants. We may here recall Sorauer's 



