a 


Igor] GERMINATION OF SPORES 47 
simple substances, but the form of Botrytis which I have used 
germinates within a few hours on large surfaces of pure distilled 
water. Moreover, the potassium compounds alone are only very 
slightly stimulating for germination, and I have found no marked 
increase in germination of Phycomyces and Penicillium by the 
addition of potassium nitrate to a solutionof sugar. The above 
remarks are also partially applicable to the conclusions which 
Molisch** has drawn from his most interesting experiments with . 
Aspergillus and Penicillium. He found no germination without 
magnesium, saying: ‘‘da ohne Magnesium nicht einmal ein 
Auskeimen der Pilzsporen stattfindet, und dieses Element weder 
durch die Elemente der alkalischen Erden (Ca, Str, Bar) noch 
durch die der Zinkgruppe vertreten werden kann.” He also 
applied these results to all “lower” fungi, that is, apparently, to 
all culturable forms. 
Pepsin and asparagin gave almost no germination with 
Sterigmatocystis. The latter substance had also very little effect 
on Aspergillus flavus, while the percentage of germination with the 
former substance was as high as ninety. 
EFFECT OF SPECIAL STIMULI ON GERMINATION. 
Under the head of special stimuli, or substances which are 
not normal sources of food supply, are also included, for con- 
venience, certain carbon compounds, as well as the metallic salts 
and mineral acids. 
In this connection an unexpected result was obtained with 
cultures of Aspergillus flavus on distilled water which had been 
Standing in paraffin-lined flasks. Nearly all of the spores on 
the edge of the drop, or where single, germinated; and a large 
per cent. of germination occurred throughout the drop. In similar 
cultures Sterigmatocystis gave usually only 10 to 20 per cent. 
of germination. Penicillium and Phycomyces were not stimulated. 
Ethyl alcohol affords a marked stimulus for the germination 
of aspergillus; germination being more nearly perfect on the 
edge of the hanging drop, but occurring markedly throughout. 
ae: “ MOLIscH, H.: Die mineralische Nahrung der; niederen Pilze. oo mmsaaagie ss 
Kaisl. Akad. d, Wiss. zu Wien 103: 554-574. 
