S. G. Paine and W. F. Bewley 



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passage of the organism through the vascular cyhnder to the cortex, 

 where it produces the typical lesions or external stripes. Ultimately, 



Fig. 3. Transverse section of a Striped stem through the browned region of the cortex. 

 The black masses indicate the attacked cell-walls which harbour the bacteria. 

 A. The distorted cells of the collenchyma. A^. Collenchyma cells showing the de- 

 struction of the middle lamella. C. Healthy cortex cells. D. Attacked cortex cells. 



however, the process was made clear by a series of transverse and 

 longitudinal sections. The bacilli work outwards towards the paren- 

 chymatous elements of the wood or the medullary rays, the cell-walls 



