1921 
ARMSTRONG—SULPHUR NUTRITION IN THE FUNGI, THIOSULPHATE 239 
in the case of the fungi. Gehring (15), Lockett (14), and 
Lieske (12), in their investigations with certain bacteria, report 
the use of the thiosulphate but not a production of hydrogen 
sulphide. Gehring found the gases produced to be 5.5 per cent 
of carbon dioxide and 94.5 per cent of nitrogen, while Lieske 
found 20 per cent carbon dioxide and 80 per cent nitrogen. 
Bokorny (12) and Nägeli (82), working respectively with yeasts 
and fungi, report the growth of the organisms on sodium thio- 
sulphate. Buchner and Hahn (703) have found that the juice 
from pressed yeast has a reducing action on sulphur and thiosul- 
phate. 
With filamentous fungi on the varying solutions containing 
thiosulphate employed by Raciborski and Kossowiez and Loew, 
other products than hydrogen sulphide as a result of the growth 
of the organisms were sulphates, sulphites, extracellular sulphur, 
intracellular sulphur, and polythionates. All of these sub- 
stances, except the sulphite, for which no tests were made, were 
found in one or the other of my cultures. The crystallization of 
the sulphur in the old hyphae of Aspergillus niger in the form of 
double pyramids as reported by Raciborski, has also occurred 
noticeably in some of my cultures in which the concentration of 
the thiosulphate was 2 per cent or more. 
It is only in very recent times that work has been done dealing 
with the actual hydrogen-ion concentration of media and the 
shifting of the hydrogen-ion concentration due to metabolism. 
Clark and Lubs (717) have given the final reaction of a culture of 
Aspergillus niger as Py 1.7. Currie (17) has given the critical 
hydrogen-ion concentration for Aspergillus niger on a solution 
very similar to that employed in experiments 16 to 21 of this 
paper as Pa 1.4 to 1.6. Steinberg (19) reported the final hydro- 
gen-ion concentration for the same fungus on Pfeffer's solution as 
Py 1.0-2.0 in most cases. On a modified Pfeffer's solution, 
the highest hydrogen-ion concentration of any culture in my ex- 
periments was Py 1.5, though the final reaction was greatly in- 
fluenced by the initial P, of the medium. Meacham ('18) 
stated that the limiting acidity appears in the region of P, 1.7 
for 4 wood-destroying fungi with which he worked. Zeller, 
Schmitz, and Duggar (19) gave the changes in hydrogen-ion 
concentration of several liquid media due to the growth of a 
number of wood-destroying fungi. The general tendency was 
