42 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



by the more numerous points of attack afforded to its spores 

 by injuries due to insects — Cahophorce, Chermes, etc., and frost 

 wounds, as well as by the longer periods of moist, dull weather, 

 and the longer season of foliation. Here we find the factors of 

 an epidemic consisting in events which favour the reproduction 

 and spread of a fungus more than they do the well-being of the 

 host." 



JVote. — The above is a resume of the matter so far as our 

 present knowledge of the disease goes, and is practically what 

 has been made out by Hartig and other authorities. 



A. W. B. 



