Mar., 1921] 
HAENSELER GROWTH OF ASPERGILLUS NIGER 
unbalanced condition of any of the solutions in any series which can be 
attributed directly to variations in the proportions of these two salts. 
Fig. 4. Triangular diagrams showing relative yields from cultures of series 4 and 5 
(group 2). Areas of low yields lie on the left margins of the diagrams, areas of medium 
yields in the central regions between dotted lines, and areas of high yields at the lower right 
of each diagram. 
Steinberg (7) reported a very marked stimulative effect upon Aspergillus 
niger from high partial concentration of MgS04 and KH2PO4, but his results 
were obtained in a culture medium essentially free from iron. The addition 
of traces of iron gave similar stimulation, and he suggests that the increased 
yields in solutions with high partial concentrations of MgS04 might have 
been due to the heavy impurities in the MgS04 rather than to the salt 
