346 Boyle . — Studies in the Physiology of Parasitism . VI. 
becomes disorganized : this disorganization extends for some little distance 
in advance of the infection hypha. 
Under similar conditions the penetration of the host may take place 
with or without the formation of appressoria. 
The method ofhyphal ‘mass infection’ displayed by Sclerotinia Liber- 
tiana is thus physiologically similar to that of infection by Botrytis cinerea 
and Colletotrichum L indemuthianum . 
It is with great pleasure that the author expresses his indebtedness to 
Prof. V. H. Blackman, at whose instigation the work was undertaken 
and from whom he has received most helpful suggestions and criticism. 
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