Aug. i6, 191S 



Nasturtium Wilt 



455 



tobacco and tomato, except when very young, wilted only slightly and 

 recovered quickly. The converse of this experiment led to the same 

 conclusion — i. e., that the nasturtium is more susceptible than the 

 tomato or tobacco — because the organism isolated from the nasturtium 

 was more infectious to the nasturtium than to tobacco or tomato. Pos- 

 sibly the susceptibility of nasturtium may be due to the great succulence 

 of the nasturtium stems. The Medan (Sumatra) tobacco organism. 



Fig. 3. — Cross section of stem of one of the infected nasturtiums from Baltimore, Md.. showing the bac- 

 terial invasion of a bundle with the beginning of bacterial cavities. Two sieve plates are visible in the 

 center phloem. 



which had been extremely virulent but had been on media for a longer 

 time than the Creedmore organism, was not able to infect either nas- 

 turtiums or tomatoes. 



EFFECT ON THE TISSUES 



The more tender parts of badly diseased plants become so translucent 

 that the occluded browned vessels may be seen clearly through the 

 water-soaked but unshriveled parenchyma (Pi. LXVI, fig. 3). In other 

 cases the course of the afifected bundle or bundles is marked superfi- 



