STUDIES IN THE PHYSIOLOGY OF THE FUNGI?! 
I. NITROGEN FIXATION 
B. M. DUGGAR 
Physiologist to the Missouri Botanical Garden, in Charge of Graduate Laboratory 
Professor of Plant Physiology in the Henry Shaw School of Botany of 
Washington University 
AND A. R. DAVIS 
Formerly Research Assistant to the Missouri Botanical Garden 
INTRODUCTION AND CRITICAL REVIEW oF LITERATURE 
The problem of the fixation of free (atmospheric) or molecu- 
lar nitrogen by the fungi has received attention at the hands 
of no small number of investigators, yet a careful study of 
the literature is sufficient to indicate that much further work 
—with the strictest regards for accurate methods—will be re- 
quired before the problem is satisfactorily solved. For rea- 
sons developed later in this paper, we have felt the desir- 
ability of continuing, under different conditions, the investi- 
gations begun by one of us some years ago. 
At the present time there can be no doubt entertained, of 
course, as to the capacity of the legume tubercle bacteria 
(Bacillus radicicola vars.) and certain soil forms (notably 
Azotobacter spp. and Clostridium Pasteurianum) to fix nitro- 
gen. Here the amounts of nitrogen-increase in relatively small 
cultures under favorable conditions are so far above any regu- 
lar experimental errors, and so consistently reported by care- 
ful workers, that the simple question of whether or not there is 
fixation is eliminated. On the other hand, there is much con- 
tradictory evidence as to the fact of nitrogen fixation by 
other bacteria and by the fungi, especially by the moulds and 
1 NorE.—About half a dozen investigations are already in progress dealing 
with the physiology of the fungi, and it is proposed to give considerable attention 
to this phase of physiology during the next few years. The investigations would 
include certain aspects of nutrition and enzyme action, growth relations—espe- 
cially the effects of environmental factors—and various phases of the general 
“Studies in the Physiology of the Fungi," of which the present article is No. 1. 
--В. M. DvGGAR. 
ANN. Мо. Bor. GARD., VoL. 3, 1916 (413) 
