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any difference with the case before mentioned, when 
those times are not the same. 
Of course it is not possible to say before-hand whether 
the drawbacks mentioned exist. 
$ 2. The drawbacks which belong to the use of the 
capillary-method. 
The method, followed till now for the experiments on 
chemotaxis, exists in this, that we put a capillary tube 
with one open end and filled with the chemotacticum in 
a preparation, holding the organisms, whose conduct we 
will examine. We wait now about ten minutes and look 
after that whether the organisms react, by controlling 
where they are. The great advantage of this method is 
that Pfeffer derived it from nature; so we can accept, 
that it will be able, at any rate as far as the spermatozoa 
of ferns are concerned, to denote which chemotactica 
could act a part biologically. Moreover the method is 
very demonstrative. 
In course of time they have required too much of the 
capillary method. The more they worked at chemotaxis, 
the more they perceived that they had to handle a very 
complicated phenomenon. Meanwhile the method remained 
the same. Yet it is easy to point out, that this has been 
a pity. We must acknowledge, that some authors have 
worked wonders with it (Pfeffer, Kniep, Shib'ata). 
Kniep has made very.important discoveries with this 
method. Kusano changed it in such a way, that he was 
able to fix the threshold in a much more exact way. 
From the publication by Kusano (1909) it appears, 
where the difficulties are, For qualitative purposes the 
method is very dangerous. Stange (1890) had worked 
with the same organism as Kusano, namely with the 
