1351 
contained in a similar old one. Various influences on the metabolism, 
such as temperature, concentration, hydrogenions, boric acid, man- 
ganese, rubidium, ete., were studied, in which only changes of velocity 
were observed. 
] have now continued these experiments, more qualitatively, with 
potassium sulfur, and magnesium and obtained the following results. 
a. Potassium. | used a nutrient liquid of the composition given in 
Table I. The constituents of the soiution in the series of experiments 
bh were the same as those of a, only no caleium had been added, 
beeause, as I have shown before, the non-adding of this element 
under the mentioned circumstances, has no influence on the velocity 
or the nature of the metabolism. This was also the case with chlorine. 
The cultivation was always effected in ERLENMEYER flasks of Jena 
glass and of 200 cm’. capacity, the volume of the medium being 
50 em*. The distilled water was once more purified in an apparatus 
of Jena glass. These experiments prove that the quantity of produced 
mould, even in the Nrs. a 1 and /1, where no potassium was added, 
is not inconsiderable. This may be ascribed to the difficulties accom- 
panying the exclusion of traces of this element. Further we see that 
by excess of potassium the spore formation is temporarily inhibited. 
Compare Nr. 5 with Nr. 4, after 4 and 5 days (Table a), and Nr. 6 
and following Nrs. with 5, after 4 days (Table 6). This inhibition 
of spore formation by an excess of a necessary element finds its 
cause in the cells being able to accumulate reserve food. *). 
Finally Table I shows that deficiency of potassium does provoke 
production of mycelium but no spore formation (Nrs. 1—3, Table I ). 
Only at gr. mol. KCl. p. L. spore forming begins after 8 days. 
37500 
Formerly *) I have shown that potassium can but partly be replaced 
by rubidium. Whereas the production of mycelium is possible as 
well with potassium as with rubidium, spore formation takes only place 
with a certain percentage of potassium and not at all with rubidium, 
It was likewise proved that manganese is necessary for the latter 
process. The results given in Table I prove that at very low con- 
centrations the action of potassium is quite analogous to that of 
rubidium: mycelium is formed, but hardly any spores, and this in 
spite of the presence of large quantities of manganese. 
In the physiological action of potassium thus, two functions are 
to be distinguished, one corresponding with that of rubidium, the 
other with that of manganese. 
1) These Proceedings, 1912. 
2?) These Proceedings, 1912. 
88* 
