762 
covered with only a small quantity of spores; the rubidium 
mycelium is moreover more intensely yellow than in normal cases, 
when it often is nearly colourless. 
The presence of rubidium in the said concentrations when kalium 
(0,1°/, KCl) is present has no influence on the spore formation and 
on the yellow-colouring of the mycelium. (See Table VI). Here it 
may be added that also the addition of 0.05 °/, manganesechloride 
accelerates the spore production. 
For the experiment I prepared two culture media of the fol- 
lowing composition. 
Medium A: Medium B: 
Distilled water in which dissolved Composed like A.; only instead 
0.2 °/, ammoniumfosfate of 0:4°/, KCT, 0:77, (REC ms 
0.1 ,, potassiumehloride added. 
0.07 ,, magnesiumsulfate 
0.035 ,, calciumchloride 
2 ” o'lucose 
Some drops of a dilute fosforic acid solution. 
In the careful investigation of BeNEcKE there is wanting an exposition 
of the relation between the assimilated food and the weight ot 
mould in connection with time. 
The results of more exact experiments are united in Table VIL. 
TAYE SL SEL MIE 
Temp. 33° °C. 
50 cm°. of the above solutions were introduced into 200 cm*. Erlenmeyer-flasks of 
Jenaglas and after boiling inoculated with Aspergillus niger. 
(Composition of the | Growth. and Spore forming after 
Nr.) * : : 
culture liquid 9 a 9 days 
11) | 50 cm? of A HH, hardly very vigorous very vigorous, 
| any spores rather many spores; many spores, myce- 
lium light yellow 
2 50 cm3 of A + idem idem idem 
+ 0,19%% KCl 
50 cm° of B idem very vigorous, very) very vigorous, begin- 
32) few spores | ning of spore form. 
mycel. orange-col. 3) 
1) In triplo 
2) In duplo. 
3) The beginning of spore formation (Nr. 3) is probably caused by the presence 
of but slight quantities of potassium. 
