195 
Chapter Ill. 
$ 1. It can easily be observed, whether the organisms 
are very movable or only little movable: By defining 
limiting concentrations, it was possible to calculate the 
critical concentration, where theoretically the transition of 
very movable to little movable took place. The motility 
was judged by means of the reaction to gravity. 
$ 2. It appeared to be necessary to let the experiments 
take place in little tubes with the same diameter. The 
influence of the temperature was of small importance. 
The experiments were done, exposed to one-sided diffuse 
day light; an attempt, to experiment in the dark, failed, 
since very irregular results were attained by it. 
$ 3. Here is discussed that the algae freed from the 
culture-fluid were brought into the electrolyte solutions. 
They were washed with distilled water for a short time. 
The susceptibility to electrolyte solutions was not changed 
by this. For every experiment was used about the same 
number of organisms. 
$ 4. In connection with the great influence of the 
H-ions and the OHions, it was desirable to have the 
solutions change regularly not only with regard to the 
salt concentration but also with regard to the amount of 
H-ions and of the OH-ions. The solutions were used in 
series. În every series the H-ion concentration was con- 
stant. The different series varied, as regards the hydrion 
concentration. By means of the series limiting concentra- 
tions were fixed and from these critical concentrations 
were calculated. The electrolytes are for the greater part 
split up into ions; it is a matter of course to attribute 
the influence of the electrolytes to the ions. In neutral 
salts the anions and the cations are always present in the 
same proportion. In salt solutions we always observe the 
influence of equal quantities of anions and cations collectively. 
