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changed. The experiments with Chlamydomonas were 
executed in a weak alcaline milieu, so the chance was 
not great to find back the series. However it was neces- 
sary to work in a weak alcaline milieu, since, otherwise 
the possibility had been great, that we compared the salts 
with a H-ion concentration, where for one salt a maximum 
and for another salt a minimum was to be found in the 
curve, which connects the critical concentrations. With 
the influence of salts on the motility of Chlamydomonas 
we have not been able to find an argument, which gives 
use to a comparison with the salting out of emulsoïds. 
AIl details, which we observed, make us think of pheno- 
mena, as they are observed with suspensoïds. Since, 
however, we have to deal with ampholytes, we are obliged 
to compare the plasmcolloïds with colloïdal substances, 
which, it is true, must be reckoned to the emulsoïds, by 
their positive or negative charge, according to their staying 
in acid or alcaline milieu, but, in connection with other 
properties they show, behave like suspensoïds. There is 
no great choise left. To the few colloïdal substances, 
which may be considered for a comparison, belong the 
globulins, to which we already drew the attention. The 
properties of the plasmcolloïds of Chlamydomonas show, 
with regard to acid, base and salt much likeness to the 
properties of the globulins. 
$ 6. Indications of a weak alkaline reaction, in the 
isoëlectric point of the plasmcolloïds. 
The H-ionconcentration, in which a colloïdal substance, 
is not combined with acid or base, is called the isoëlectric 
point. According to Michaëlis (1914, page 39) ampholytes 
are isoëlectric, when by a special concentration of the 
ampholyte, the sum of anions and cations of it has reached 
