276 



BIOLOGY OF SPECIALIZED GROUPS 



Present Conception. Against the opinion of these few 

 investigators will be found the majority of pathologists 

 and bacteriologists. It is now agreed by the leading au- 

 thorities that there are distinct bacterial diseases of plants. 



FIG. 53. Soft rot of green cucumbers inoculated with B. carotovorus. (Pure 

 culture inoculation.) After Smith. 



These diseases can be produced in the various species of 

 healthy plants by inoculation with definite species of bac- 

 teria (Fig. 53). 

 Species of bacteria have been repeatedly isolated from dis- 



