452 



Pr..f. M. < . h.ttrt. On " i 



the destruction of the middle lamella and the separation of the 

 cells. 



Fig. 5 shows a cell swannini; with /'. <l>:<l,-in-l"ii* ; the bacteria are 

 seen occupying the inter-cellular space- and lyinii i" the track of the 

 middle lamella. 



Fig. 5. A cell from turnip inoculated with a pure culture of P. 



The bacteria are seen in the cell cavity and also along the track of the 

 middle lamella, and in the intercellular spaces. The cell-wall is much 

 swollen ; at a it is just beginning to separate along the middle lamella 

 and at b the dissociation i.- more strongly marked. The nucleus and 

 portions of the protoplasm still remain. (Drawn with Abbe camera 

 lucid?, Zeiss, E. oc. 4.) 



In the case of several parasite fungi, the hyphse also burrow in the 

 thickness of the cell-wall, and the same phenomenon is now shown to 

 be true of one parasitic schizomycete, and possibly this is owing to 

 the necessity for the neutralisation of the oxalic acid as a condition of 



existence. 



% 



Enzymes similar in nature to that described for P. dfttnutaM have 

 been demonstrated by Marshall Ward for Ptoti-iiti* and by de Bary for 

 Sderotfaia. 



The action of this bacterium upon living plant tissues is precisely 

 similar to that of certain of the parasitic fungi; in both cases the invading 



