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compared the influence of the chemotactica with the action 
of electrolytes on colloïds. Now it is my intention to prove, 
that when studying chemotaxis we may not forbear to 
examine the colloïd-chemical phenomena. 
The very first argument for colloïd-chemical opinion, 
is that one generally accepts, that the protoplasm is 
colloïdal. Then the suggestion follows that the influence 
of the chemotactica is a colloïd-chemical one. The active 
concentrations may be very small When we find acid- 
concentrations of 0,0001 normal and still smaller chemo- 
tactically active on numerous organisms, we can best form 
an opinion of it, when we accept, that we have to do 
with phenomena from colloïdchemistry. À further argument 
might be found in the nature of the substances. It is 
known, that particular special ions often have a great 
influence on colloïds. That is the case with the hydrions 
and the hydroxylions We have already seen, that the 
hydrion plays a great part in chemotaxis too, provided 
we may accept, that with the activity of acids the hydrion 
exercises the greatest influence. For the hydroxylions we 
can also find an example Shibata states, that the 
spermatozoa of {soëtas are attracted by the hydroxylions. 
Besides these two ions there are a lot of others, which 
are very active sometimes. Às regards these, however it 
is still more difficult to find conformities in colloïdchemistry 
and with the chemotaxis. This is brought about by the 
fact, that we cannot very well make out with what colloïds 
we have to compare the protoplasm. In colloïdchemistry 
we distinguish two large groups of colloïds. The suspensoïds 
are susceptible to very small quantities of neutral salts. 
The valence of the ions acts a great part; polyvalent ions 
have an immense effect. The suspensoïds are charged 
either positively or negatively. Especially ions with an 
antogonistic charge have a great influence on the statility; 
we cannot see much of the influence of the other ions. 
