ILLUSTRATIONS OF PHYTOPHTHOEA INFESTANS. 425 



paration from which fig. 13 was drawn it was easy to see the 

 remaius of the protoplasm as a sort of matrix in which the 

 starch-grains (some partially eroded) were embedded. The 

 nucleus and proteid seem to be destroyed long before the 

 starch, and it is even doubtful whether the starch is directly 

 attacked at all until bacteria gain access, and hasten the de- 

 composition. In fig. 13 starch grains are seen to be displaced 

 from the matrix in which they were lying. 



Fig. 14. — Portion of mycelium from such a preparation as the 

 last. The two branches running across from the vertical ones 

 were passing along the surface of a cell, and a brownish tinge 

 was given to the cell wall in the immediate neighbourhood. 

 The same is seen in fig. 15, a and b. The hypha corrodes the 

 walls, as it were, in its immediate neighbourhood : the rest of 

 these cell walls were as yet not coloured. 



Fig. 15. — Portions of hyphae in the middle lamella between 

 the cells of the potato tuber. The corrosive action of the 

 hyphae is indicated by the rusty hue which they cause the cell 

 walls to assume. 



