NEUROBIOTAXIS Ze Al 
As third example of galvano-taxis the phenomenon discovered 
by Verworn'’ in one-celled creatures must be mentioned here, 
viz., that these (ameba, for instance) on the transmission of a 
constant current through the surrounding medium, send out 
enlargements and finally shift in the direction of the kathode. 
Verworn at first held the opinion that there were also Pro- 
tozoa which shift under normal circumstances to the anode, and 
he therefore made a distinction between kathodic and anodic 
galvano-taxis. Later investigations revealed that the anodic 
galvano-taxis must be considered as being something diffe:ent 
from the kathodic, and that the direction and shifting of the 
bodies observable in Protozoa under normal circumstances is 
invariably a kathodic galvano-taxis. 
Also Boruttau (personal communication) holds the opinion 
that every real galvano-tropism is a kathodic stimulation phe- 
nomenon. ‘This usual kathodic galvano-tropism can be brought 
into correlation with Pfliiger’s law, as has been pointed out by 
Loeb and Maxwell.” 
As far as the anodic tropism is concerned, Loeb and Budgett?’ 
and after then Coehn and Barratt?! found that when a proto- 
zoan, Paramecium, in pure water or in a weak solution of common 
18 Verworn. Die polare Erregung durch den galvanischen Strom. Pfliiger’s 
Archiv, Bd. 45, 1889. Verworn. Die polare Erregung der Protisten durch den 
galvanischen Strom (Fortsetzung). Pfliiger’s Archiv, Bd. 46, 1890. Verworn. 
Untersuchingen tiber die polare Erregung der lebendigen Substanz. 3te Mittei- 
lung. Pfliger’s Archiv, Bd. 62, 1896, S. 415. Verworn. Die polare Erregung 
der lebendigen Substanz durch den Constanten Strom. 4te Mitteilung. Pfli- 
ger’s Archiv, Bd. 65, 1897. 
18 J. Loeb und 8.8. Maxwell. Zur Theorie des Galvano-tropismus. Pfliiger’s 
Archiv, Bd. 63, 1896. 
See also J. Loeb und Walter Gerry. Zur Theorie des Galvano-tropismus, IT. 
Versuche an Wirbelthieren. Pfliiger’s Archiv, Bd. 65, 1897, S. 41. J. Loeb. 
Zur Theorie des Galvano-tropismus, III. Ueber die polare Erregung der Hart- 
drusen von Amblystoma durch den Constanten Strom. Pfliiger’s Archiv, Bd. 65, 
1897, S. 308. 
20 Loeb und Budgett. Zur Theorie des Galvano-tropismus. IV. Mitteilung 
iiber die Ausscheidung electropositiver Ionen an der ausseren Anoden flache 
protoplasmatischer Gebilde als Ursache der Abweichungen vom Pfliiger’schen 
Erregungsgesetz. Pfliiger’s Archiv, Bd. 65, 1897, S. 582. 
21 Coehn und Barratt. Ueber Galvano-taxis von Standpunkt der physio- 
logischen Chemie. Zeitsch. f. allgemeine Phyziologie, Bd. 5, 7, 1905. 
