1916] LINK—FUSARIUM 199 
would have to destroy a tissue whose walls are mainly cellulose 
by intercellular activity, while one that could digest cellulose might 
Fic. 13.—Fusarium tric hothectoides and F. yonnerst on n sterile potato cylinde Ts; 
A, C, cylinders inoculated with F. cysporum, incubated for 2 days at 25° 
se -~° (> 
cylinder inoculated with F. iricholbectoides incubated for 2 pill at 25° C, 
destroy this tissue by a primary cell invasion. Again, a greater 
ability on the part of an organism to digest suberin, other things 
