1921] 
WEBB—GERMINATION OF SPORES OF CERTAIN FUNGI 315 
DISCUSSION 
Germination of fungous spores is a subject that has engaged 
the attention of botanists—physiologists and pathologists—for 
many years. Various aspects of the problem have been ex- 
tensively studied, and certain factors, such as temperature, 
light, moisture, and reaction of the medium have been experi- 
mentally considered. The toxic properties of H and OH ions 
have been treated more or less, but hydrogen-ion concentration 
has so recently become biologically important that the influence 
of this factor in germination was practically new. Having no tech- 
nique they could apply for the direct determination of hydrogen- 
ion concentration, the earlier investigators, like many of the 
later ones, frequently employed conductivity data in making 
their interpretations. This method is, however, inapplicable 
when other solutes are introduced, and the presence of strong 
buffers, whether inorganic or organic, would render most difficult 
any computation of active acidity or alkalinity. 
It is believed that the results here presented are sufficient 
e á EN A 
RBE i INS 
I 
1| A AS 
R 6o 4 A 
é d 23% ' 
TA E N 
bad | 
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oy 
2 3 +t- $: 6 7 8 3 
D 
Fig. 11. Aspergillus niger in sugar beet decoction. 
to change materially the prevailing view as to the relation of 
spore germination to acid and alkaline media. Although ger- 
mination, as related to active acidity and alkalinity, varies with 
the organism and with the liquid culture medium, it is a process 
