43 



BULLETIN 387 



in figure IOO,B, gives no indication as to where penetration occurred. 

 Yet by moving the section the length of half a dozen cells, there is seen 

 an uninterrupted connection of diseased tissue between this particular 



row and the epidermis 

 (fig. i oo, A). 



So far as the writer's 

 observations go, there 

 seems to be no question 

 but that penetration 

 does take place thru the 

 root hairs, and thru 

 these only. Eycle- 

 shymer (1894) suggests 

 that wounds caused by 

 insects may provide a 

 means of entrance for 

 the parasite. This is 

 altogether probable ; yet 

 the writer has never 

 observed any indica- 

 tions of this condition, 

 so that if it ever hap- 

 pens it apparently does 

 so very rarely. If cul- 

 tures could be secured 

 within pieces of healthy 

 disinfected roots in test 

 tubes, it would at least 

 be evidence that such 

 wound infection might 

 take place. Pinoy(igo5) 

 removed small pieces of 

 nealthy roots by means 

 of sterilized pipettes, 

 and by inoculating them 

 TISSUE OF A CABBAGE w ith spores secured cul- 

 tures of the organism, 

 provided the tubes were 

 sealed so that the aerobic 

 bacteria were deprived of oxygen. His discussion of this point is some- 

 what lacking in clearness. Besides, the time in which he claims spores 

 were produced in the roots is unusually short. He gives it as five days, 



FlG. IOO. DISEASED 



CORTICAL 

 ROOT 



A, A row of diseased cortical cells; B, another row of diseased cor- 

 tical cells connected with the epidermis by an unbroken line of diseased 

 tissue. X no 



