[Vor. 8 
284 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
point are: Is the effect of the hydrogen- and hydroxyl-ion con- 
centration upon the rate of germination of the spores of certain 
fungi the same in different types of media? Is the range within 
which the most favorable germination occurs the same for 
different types of media? What relation does nutrition bear, if 
any, to the toxicity of the hydrogen- and hydroxyl-ion concentra- 
tion during germination? And, if certain differences in effect 
exist, what are the explanations of such phenomena? These 
questions, together with others, suggested the desirability of 
conducting the investigation reported in this paper. Using the 
spores of 8 fungi a comparative study has been made dealing 
with the effects of hydrogen- and hydroxyl-ion concentrations 
upon germination (1) in water, (2) in such single nutrient solu- 
tions as mannite and peptone, and (3) in such full nutrient 
solutions as Czapek's solution and sugar-beet decoction. 
LITERATURE 
The literature concerning the germination of fungous spores 
and their subsequent growth and development, as related to 
the reaction of the medium, has been historically considered 
by the writer in an earlier paper (Webb, '19). These articles 
together with certain others—as reviewed below—are completely 
cited in the bibliography of this paper. 
Buller (^06) obtained a high germination percentage with the 
spores of Polyporus squamosus in a malt-wort extract, the reaction 
of which was slightly acid. He prepared a solution with tap 
water, meat extract, 0.5 per cent, peptone, 0.5 per cent, grape 
sugar, 3 per cent, and gelatin, 10 per cent, adding sodium 
carbonate until distinctly alkaline. The mycelium grew in this 
mixture more vigorously and branched more frequently than in 
the malt-wort extract. In a decoction made from the wood of 
Acer pseudoplatanus, no germination occurred during the first 
2 days, but about 1 per cent of the spores had germinated on 
the third day. However, bacteria had developed abundantly in 
the culture. Buller says: ‘‘The impression given me by this 
exceptional case was that the metabolism of the bacteria had 
given rise to some substance which to a slight extent had stimu- 
lated the spores to germinate." A change in reaction of the 
medium may have been a contributing factor, but no mention 
is made concerning this point. 
