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BACTERIAL DISEASES OF PLANTS 



21, 1902) leaves me in doubt. No one now has transfers from 

 van Hall's original culture, I believe, so as to enable one to clear 

 up the doubtful points and under the circumstances it is best, 

 I think, to retain Appel's name, especially as van Hall made 

 very few inoculations under natural conditions and as he says 

 of his organism: "On artificial media the parasite loses its 

 virulence very quickly." Moreover, if May 21, 1902, or some 



% 



^ 



Fig. 203. — -Stained section of a potato tuber in the vicinity of an infected 

 lenticel (stage of Fig. 202) showing bacteria dissolving the middle lamella and 

 wedging apart the starch-bearing cells. 



later date is the actual date of publication of van Hall's thesis, 

 then Appel's name is at least 2 months earlier than van Hall's 

 name and the latter, even if synonymous, does not have priority. 

 To isolate this organism, the surface through which it is 

 proposed to enter for cultures should be burned with a hot 

 knife or spatula, or soaked for twenty minutes in 1 :1000 mercuric 



