232 



BACTERIAL DISEASES OF PLANTS 



the surface colonies (Jones 3a, stock long in my laboratory) are 

 sometimes more or less irregular in outline and may send out 

 finger-like branched projections (Fig. 177). Fearing that in 

 some transfer the labels of Bacillus aroideae and Bacillus caro- 

 tovorus might have been interchanged I sent to Wisconsin in 

 1920 for another culture of 3a and this in agar-poured plates 



Fig. 173. — Detail from Fig. 172 at A'. Much enlarged to .show the bacteria dis- 

 integrating the swollen cell-wall and confined to the intercellular spaces. 



gives round colonies (Fig. 178). The two stocks also differ in 

 amount of gas formed from potato juice (Fig. 179) and in other 

 ways. 



On the +10 gelatin-poured plates the margins of the young 

 surface colonies (X125) are thickly set with parallel filamentous 

 outgrowths (Figs. 180, 181), this fimbriate margin being about 

 50fjL wide on the second or third day. The buried colonies 



