1921] 
WEBB—GERMINATION OF SPORES OF CERTAIN FUNGI 337 
(2) Suecessively increasing concentrations of hydrogen ions 
in the various culture solutions, from neutrality to approximately 
Py 3.0 or 4.0, influence favorably the germination of the spores 
of B. cinerea, A. niger, Penicillium cyclopium, P. italicum, Puccinia 
graminis, L. saepiaria, and Fusarium sp. Moreover, Fusarium 
sp. germinates equally as well, if not better, with an alkaline 
reaction, and C. Gossypii is the only species which favorably 
responds only to an alkaline reaction. 
(3) The majority of the fungi employed exhibit a distinct 
maximum of germination between Px 3.0 and 4.0. Certain forms, 
notably Fusarium sp., exhibit secondary maximum at or near 
Pg 7.0. 
(4) The range of germination and the magnitude of the 
germination quantities, as influenced by the hydrogen-ion con- 
centration, depend upon both the organism and the medium. 
(5) It is not until a hydrogen-ion concentration of Pg 1.5-2.5 
is reached that inhibition of germination is evidenced. The 
limits on the acid side are comparatively narrow and constant. 
Those on the alkaline side are very diverse, varying with the 
organism and with the medium. 
(6) Nutrition is an extremely important factor in the germina- 
tion of fungous spores. In solutions of mannite, Czapek, and 
peptone, the relations of germination to hydrogen-ion concentra- 
tion are more or less comparable for each particular organism; 
in beet decoction and * water HCl or KOH," on the other hand, 
results differing decidedly from those furnished by the previously 
mentioned solutions are obtained. 
(7) Solutions of *water HPO, and NaOH," followed by 
those of mannite, undoubtedly give the smallest range of germina- 
tion and the lowest percentages of germination. Solutions of 
bacto-peptone give very similar results to those developed in 
solutions of mannite, except that germination is better and is 
extended slightly more to the alkaline side. Czapek’s full 
nutrient solution generally exhibits ranges similar to those 
furnished by the peptone solutions, but the curves of germination 
differ. In the Czapek solution, two maxima usually occur: a 
primary one between Px 3.0 and 4.0 and a secondary one between 
Ps 6.0 and 7.0. Of all the media employed, beet decoction 
