176 ROYAL SOCIETY OF CANADA 



Cross inoculations have not been observed. Pea and vetch growing 

 in the same flask, which was inoculated with vetch culture, formed 

 abundant nodules, and root infection occurred in the vetch, but the pea 

 showed no infection whatever. Ps. radicicola was isolated from the 

 nodules on this vetch and plates from the peas were negative. The 

 like was true of bean and pea growing in the same flask and inoculated 

 with pea culture. ISTodules formed on the pea only. 



The notes regarding the growths of legumes in all our flasks are 

 not given, but a few samples will suffice to give the necessary inform- 

 ation regarding the inoculations, growth of plants and methods of isola- 

 tion ; and we wish to point out the value of this method to any one 

 engaged in biological problems associated not only with legume bacteria, 

 but also with the bacterial and fungus diseases of plants. All condi- 

 tions are better under control and seem to us to offer advantages over 

 the methods devised by Marshall Ward in his study of certain rusts. 



Flasli- Cultures. — Seeds of Vicia, villosa were taken from the pods 

 under sterile conditions, July 2nd, 1904, and were distributed in tubes 

 containing sterile water, December 29th, 1904. By January 1, 1905, 

 eight seeds had germinated and all were free from bacteria. The water 

 in the tubes was clear and stains from it were negative. 



One seed was planted January 1, 1905, in each of seven 1,000 c.c. 

 Erlenmeyer flasks containing each 200 c.c. of ash-maltose-agar, E51. 

 The cotton plug was removed, the seed was dropped into the flask by 

 means of flamed forceps and the radicle was pressed into the agar by 

 means of a flamed and cooled glass rod. The plug was replaced in 

 the mouth of the flask. The flasks were then kept in the window of 

 a living room and on sunny days were protected by a piece of cheese 

 cloth. 



The culture used to inoculate flasks I, III and V was isolated from 

 a nodule of Vicia villosa on July 6, 1904, in ash-maltose-agar K34, 

 and a colony was transferred to E44, July 11, 1904. A single needle- 

 ful of the gro\\i;h on E44 was used to inoculate all three flasks January 

 7, 1905. In two days there was growth of the culture in the inocu- 

 lated flasks. This growth increased rapidly and in eight days there 

 was a copious, wet-shining, mucilaginous layer covering nearly tihe 

 whole surface of the agar. This growth now began to accompany the 

 growing roots, and from this time on every ramification of the roots 

 was surrounded by a thin cylinder of bacterial growth. This growth 

 penetrated the solid agar a little distance in advance of the growing 

 root tips (see photographs 35, 36 and 37). 



!Plasks II, IV, VI and VII were not inoculated and no bacterial 

 nodules appeared on the roots of these plants. 



