Bacteria in their Relation to Vegetable Tissue. 



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TABLE SHOWING ACTION OF ANIMAL PABASITIC FORMS IN 

 VEGETABLE TISSUE. 



1 Numbers in parenthesis indicate number of colonies found in culture made from 

 infected tissue. 



It is noteworthy in the above table that the pyogenic organisms 

 in general do not seem to be especially resistant. With the single 

 exception of the blue pus-germ, they succumbed to the unfavorable 

 influence of the plant-tissues. 



The consideration of the third class, that of bacterial plant para- 

 sites, brings us to those forms which are, in a restricted sense at least, 

 the natural enemies, of vegetable life. 



I have found it impossible to obtain cultures of more than a few 

 of the germs which have been reported as having been isolated in the 

 various plant-maladies, as in many cases cultures are not kept in 

 stock, even by the discoverers of the germ. 



Of those secured I made a series of infection experiments in a 

 number of different hosts, to ascertain the effect of vegetable tissues 

 in other than their natural hosts. 



The pear-blight germ grown in a Begonia-plant for 30 days showed 

 at end of that time large numbers at inoculation point, but not dis- 

 tributed throughout the plant. The same result was found when 

 injected into Phaseolus vulgar is for 30 days, also in Ph. lunatus for 

 16 days. In Tradescantia alba, no trace could be found at the end 

 of 60 days' incubation in this tissue. Bac. avense was injected into 

 tissue of Begonia, onion, corn, wheat, and squash, but in no case 



