( 600 ) 
together a mouse was driven to and fro in a cage, without granting 
it any rest; after that the exhausted animal fell asleep or at any 
rate remained perfectly quiet. The control-animal was kept in perfect 
repose. Both animals were then killed, and small pieces of the 
brain were immediately fixed after the method of Gone. He 
obtained manifest results already when only feebly magnifying: the 
collaterals of the dendrites have vanished, instead of these the 
dendrites have globular tumefactions, retracted branchings which 
seem to have loosened themselves from the neighbouring end-arbor- 
isations. 
MANOUELIAN writes: 
“On pense, en présence de ces images, a celle d’une sangsue vue 
comparativement dans l'état d’élongation et dans l'état de rétraction 
en boule.” 
Previous to these experiments, RaBr-RückHarpr had published a 
theory on the amoeboid motion in the cells of the central nerve- 
system, a theory not founded however on mieroscopical data. (Neurolog. 
Centralblatt 1890, p. 199). The investigations of WiepersHeiM who 
experimented on a living Crustacea, Leptodora hyalina, and those 
of Prreens and others on the retina of Leuciscus rutilus, seemed to 
confirm the conjectures of RABL-RücKHARD. 
WiepersHem has been able to follow the motion of the processes 
of the nerve-cells with the microscope and arrives equally at the 
conclusion: “dasz die centrale Nervensubstanz nicht in starre For- 
men gebannt, sondern dasz sie activer Bewegungen fahig ist.” 
J. Demoor injected dogs with lethal dozes of morphia, and studied 
a small piece of the cortex cerebri, which he extirpated before the 
death of the animal. He too, and likewise SrrraNowska, after injecting 
mice with ether, found similar changes as observed by MANovgLIAN: 
the branchings having become smaller and shaped like a string 
of beads. 
Two american authors however, Frank and Wein, did not obtain 
these results on animals under narcosis. 
In order to obtain some certitude whether any differences might 
in reality be observed, I tried a few experiments in the laboratory 
of Professor WINKLER. 
Firstly I did repeat the experiments of STRFANOWSKA and DEMOOR, 
albeit the methods employed were not in every respect the same 
as theirs. 
The mice were brought under narcosis by means of chloroform 
instead of ether: immediately after death they were decapitated, the 
head was caught into a liquid, prepared after the method of Gore1 
