EXPERIMENTS WITH THE ARBUTUS ORGANISM. 53 



well, i. e., the careless breaking of lai^e roots. They were an inch or 

 two in diameter at the base when inoculated and have made a slow 

 growth. The areas punctured by the needle are still plainly visible 

 on the yellow bark of the roots as little black patches. 



DAISY ON ONION. 



Inoculations of January 6, 1907 (Brown). 



The bulbs (part above ground) and also the leaves of Allium cepa 

 were inoculated by needle pricks with agar streak cultures 4 days old. 

 Three checks were held. 



Result. — February 1, 1907: No knots formed. 



Inoculations op April 4, 1910 (Brown). 



Eleven onion plants, growing slowly, were pricked in the bottom 

 of the plateau from an agar streak culture of newest isolation. 

 Result. — June 24, 1910: All negative. 



EXPERIMENTS WITH SCHIZOMYCETES FROM GALLS ON OTHER 



PLANTS. 



In connection with our studies of the organism derived from the 

 cultivated daisy, isolations from galls on other plants, together with 

 pure-culture inoculations and cross-inoculations, were undertaken as 

 follows: 



HONEYSUCKLE ON DAISY. 



Inoculations of April 14, 1908 (Smith). 



Eight daisy plants were inoculated by needle pricks wdth agar 

 streak cultures 4 days old of an organism plated out of an old knot 

 on Japanese honeysuckle, found near Washington by Mr. W. A. Or- 

 ton. The honeysuckle knots were about one-fourth inch in diam- 

 eter. The knot from which these cultures were made was somewhat 

 cracked open, and the plates came up with a variety of bacterial col- 

 onies, white and yellowish. A half dozen of these colonies approach- 

 ing the daisy organism in appearance were selected, from which trans- 

 fers were made. 



Result. — June 1, 1908: No tumors. This means perhaps that the 

 two colonies selected for these inoculations were not the right thing. 



ARBUTUS ON DAISY. 



Inoculations op November 2, 1909 (Brown). 



Five young daisy plants were inoculated with agar cultures 5 days 

 old plated from gall on Arbutus unedo sent from France. The daisy 

 plants were of the lot obtained from a grower in Boston and were in 

 splendid condition. Several checks were held. 



Result. — March 26, 1910: No galls formed on any of the plants. 



213 



