CAUSE AND NATURE OF CROWN-GALL 63 



SPORE INOCULATIONS. 



December 5, 1899, ripe spores were carefully removed from 

 a sporangium by touching them with the tip of a moistened 

 needle and inoculations made at the crowns of four one-year-old 

 almond seedlings growing in the greenhouse. 



January 2, 1900, one of these plants had galls developing at 

 the point of inoculation. 



December 20, 1899, six almond seedlings about four months 

 old, growing in a pot of sterilized soil, were inoculated with 

 great care as follows: The peridium was carefully removed from 

 a ripe sporangium, a moistened needle inserted, and the spores 

 which adhered to the needle point were transferred to a needle 

 wound at the crown of each plant. January 20, 1900, the plants 

 were examined and two were found with developing galls at the 

 point of inoculation. 



COMPARISONS WITH SOME RECENT INVESTIGATIONS ON 

 PLASMODIOPHORA. 



I fully recognize the incompleteness of this investigation and 

 the uncertainties regarding certain portions of the work, but, as 

 other duties make it necessary for me to lay aside the work for 

 an indefinite period, I believe it best, on account of the great 

 economic importance of the disease, to publish the results that 

 I have obtained without waiting to make additional spore in- 

 oculations or to complete certain cytological investigations 

 which I have in view and hope to make as opportunity per- 

 mits. 



Just as this paper was ready for the press I obtained a copy 

 of Dr. S. Nawaschin's recent investigations of Plasmodiophoi a." 

 In Dr. Nawaschin's investigations the diseased tissue of the 

 cabbage was fixed in strong Flemming and, with one or two 

 modifications, stained in the usual way. As my work was not 

 influenced in the least by that of Nawaschin, and as the dis- 

 eased almond roots with which I worked were also fixed in 



42 Nawaschin, Dr. S. — Beobachtungen iiber den feineren Ban und Um- 

 wandlungen von Plasniodiophora brassicse Woron. im Laufe ihres in- 

 tracellnlaren Lebens. Flora, 86 Bd., 404, 1899. 



