1922] RAYNER—NITROGEN FIXATION 235 
writer, who showed also that seedlings of Calluna vulgaris in pure 
culture thrive in a rooting medium lacking combined nitrogen. 
3. In 1916 Duccar offered additional evidence for fixation of 
nitrogen by members of Phoma. ‘ 
The experimental work of which this paper gives an account 
has been in part carried out at the Pilcher Research Laboratory, 
Bedford College, University of London, with the aid of a grant 
from the Dixon Fund of the University of London. 
BEDFORD COLLEGE FOR WoMEN 
UNIVERSITY OF LONDON 
