H. L. Russell. 



was any pathological change macroscopically observable. The 

 bacilli were not killed out in the plant-tissue, however, as they were 

 isolated from Begonia and squash in large numbers, after 30 days 7 

 incubation in these tissues, but their presence was confined to the 

 tissue contiguous to point of introduction. 



The results of the foregoing inoculation experiments made with 

 various forms of micro-organisms, saprophytes as well as parasites 

 (both for animals and vegetables), show that these germs in many 

 cases are able to live in the plant-tissues for a considerable length of 

 time. A number of the different forms, particularly saprophytes, 

 are able to grow and spread throughout the plant to a limited 

 extent. Of the parasitic species tested, very few showed any ten- 

 dency to thus spread. Even those forms that are natural parasites 

 of certain higher vegetable species showed no power to spread in 

 plants which were not their natural hosts, but they were able to live 

 at inoculation-point for a considerable time. 



The possible objection, already alluded to, that the distribution of 

 the bacteria, which was noted in many cases, may not indicate actual 

 growth, will now be considered. 



The observed facts are these: The distribution of the micro- 

 organisms in the plant-axis, as determined by culture experiments, 

 always took place in an ascending direction. This distance varied 

 from 30-50 mm. from point of introduction, but in no case were bac- 

 teria found more than 2-3 mm. below inoculation-point. 



Of course the numbers given above do not represent the total 

 number of bacteria present, owing to the difficulty of preparing tissue 

 so that all can develop. Besides this fact, the developing colonies 

 were observed to be usually intracellular and not in the spaces of the 

 plant. 



