REPORT OF THE SOCIETY: 111 



water, then in mercury bichloride 1: 1000, and afterwards rinsed twice in 

 steiiL water to remove all traces of the mercmic chloride. These slices were 

 then placed in sterile petri plates ready for inoculation. In the bottom of each 

 plate there was placed a piece of sterile filter paper, which was kept moist with 

 sterile water while the cultures were under observation. 



Carrot inoculations. 



The carrot plugs were inoculated on October 28th from agar slope culture 

 thirty-six hours old. The inoculum was placed on the surface of the plug which 

 was then gently pi-icked with a sharp sterile needle to give the bacteria access 

 to the normal tissues, in case some of the exterior cells had been killed by the 

 mercuric chloride. After inoculation the plugs were incubated at 27oC. 



At the end of the third day the cultures were examined with the following 

 results; — la and 3a showed considerable bacterial growth on the surface of the 

 plug, 4, 7a and 10 showed slight growth, 26b showed considerable growth and 

 apparently slight rotting, and 19b showed growth over the entire surface of 

 the plug and also in the hquid in the bottom of the petri plate, but there was 

 practically no appearan(?e of rot. The remaining slices showed absolutely 

 no signs of infection whatever and could not be distinguished from the check 

 cultures. 



After five days the results were slightly more pronounced. In all cases the 

 infections described above were somewhat increased and in addition 15 showed 

 slight bacterial growth on the surface of the plug. 



In all cases where infection had been obtained, isolations were made to agar 

 slants and labelled with the letter "C" after the organism that had caused the 

 ot. Thus, for example, the organism which had been isolated from the rot 

 caused by "4" was labelled "4C" a)nd so on with all cases. 



Iris Plug Inoculatons. 



On November 16th, slices of Iris rhizomes were inoculated in a similar 

 manner with forty-eight hour old cultures of all the original organisms and also 

 the organisms that had been isolated from the infected carrots. These were 

 incubated at 27oC, and after two days the folloiving results were recorded; — 2, 

 3aC, 7a, 7aC, and 26bC showed definite signs of rotting of the rhizome tis- 

 sues while 4C, 15, and 15C showed only slight rotting. As the time increased 

 there was no change except that the rotting gradually increased and that the 

 plug inoculated with 7aC showed a definite increasing pink colour. 



As was done with the carrot inoculations, isolations were taken from the 

 various rots produced and the letter "I" placed after the symbol of the original 

 infecting organi m. 



