OTHER BACTERIAL DISEASES. 39 1 



the bacteriosis of carnations, black disease of maize, gall of the 

 pine, canker of the ash, canker of the ivy, lilac disease, black 

 disease of nmlberry, red coloration of ivheat, and some forms of 

 potato scab have also been claimed to be produced by bacteria. 

 The evidence is conclusive in regard to the first three. In 

 regard to the others the evidence is not quite conclusive, and it 

 may be that some of them have an entirely different explana- 

 tion. However that may be, the first ten mentioned have been 

 so conclusively demonstrated to be caused by bacteria, that we 

 cannot longer question the causal connection of the bacteria 

 and the diseases. Bacteria are thus of very great significance 

 in producing plant diseases and will in the future, doubtless, be 

 of far more interest to agriculture than they have been in the 

 past. 



