Bacteria in their Relation to Vegetable Tissue. 3 



I have been unable to find any literature upon this particular 

 question with the exception of a preliminary report by Lominsky, 

 who worked mainly with those forms which are pathogenic for 

 animals. His original paper is in Russian, so I have been forced to 

 rely solely upon an abstract (Cent, fur Bakt., Bd. VIII, 325) for 

 his data. 



Aside from this single exception, I find no general series of 

 experiments recorded as giving the effect of vegetable tissues upon 

 various forms of bacterial life. 



METHOD OF EXPERIMENT. 



The following outline will indicate the manner in which the 

 experiments were carried out. Fresh cultures of the various micro- 

 organisms were always taken (usually bouillon cultures 12-24 hrs. 

 old), so as to insure the introduction of non-sporogenous material. 

 A young growing stem was selected, so as to give the most favorable 

 conditions for the, development of the organism. It was first washed 

 with sterile water and then pierced with a fine sterilized platinum 

 needle. Into this minute opening a tiny droplet of culture fluid was 

 injected from a capillary pipette. The slight puncture caused by 

 the penetration of the needle was then closed from the influence of 

 air and possibility of accidental contamination, by sterile vaseline. 



The results were determined by excising a section of the infected 

 stem, the surface having been slightly flamed in a Bunsen flame. 



The cortical layer was then removed with a sterile scalpel, leaving 

 the inner tissue into which the organism had been injected. Quite 

 thin sections of this remaining tissue were cut, under aseptic precau- 

 tions, and inoculated into tubes of melted gelatine and roll cultures 

 made therefrom. As the fluid gelatine easily penetrates the plant- 

 tissue, a moderately thin section may be examined, under considerable 

 magnification, with ease. The tissue was sectioned, not only at the 

 inoculation point, but at varying distances above and below. By 

 growing these serial sections in sets of culture tubes, one is able to 

 determine how far the bacteria have spread .throughout the plant. 



An objection to this method lies in the fact that small variations 

 in the germ-content cannot be detected, as it is quite impossible to 

 prepare the tissue so that all germs present can develop ; but where 

 cultures made from tissue taken at the point of inoculation reveal 



