[Vor. 8 
338 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
gives the best germination and the widest range of germination. 
Germination in this medium, as well as in “water HCl or KOH," 
occurs freely under conditions of active alkalinity, producing 
inhibition of germination in the other media, and germination 
is stimulated to such an extent that the maxima cover relatively 
wide zones. 'The same may be said of the peptone medium, 
though the magnitude and the frequency are less. The other 
media, namely, mannite, Czapek's solution, and water, exhibit 
distinet maxima in the form of sharp peaks. 
(8) Mycelial growth and development in the most acid and 
alkaline eultures permitting germination are relatively more 
feeble and scant, as determined visually, than in cultures possess- 
ing greater departures from the inhibiting concentrations. 
Rudimentary germ tubes or knob-like projections frequently 
oceur in the most alkaline cultures, and abnormally and irregularly 
shaped germ tubes generally develop in the most acid cultures. 
(9) Comparing equal concentrations of H and OH ions, the 
OH ions appear to be relatively more toxie to the spores studied 
than H ions. The toxicity of H ions is fairly independent of 
the other conditions studied, while that of the OH ions tends 
to be more or less variable or antagonizable, according to the 
composition of the medium. 
(10) A change in reaction of the medium may or may not 
occur during germination, and, where shifts in the hydrogen-ion 
concentration do occur, the magnitude and nature of these 
depend upon the fungus, the medium, and the initial reaction. 
While growth stages are marked by pronounced changes in 
reaction of the medium, A. niger produces no changes in reaction 
while germinating in the solution of mannite and in Czapek's 
medium, but does produce certain shifts towards neutrality in 
the alkaline cultures of the beet decoction. B. cinerea induces 
no changes in the reaction of the medium while germinating in 
solutions of mannite, Czapek’s solution, “water H,PO, and 
NaOH,” and ‘‘water HCl or KOH” but does produce a change 
in the beet decoction similar to but less than that of A. niger. 
The only conspicuous change brought about by germinating 
spores of Fusarium sp. is in “water HCl or KOH," all of the 
cultures giving favorable germination exhibiting a shift in re- 
action towards neutrality or slight alkalinity. 
