406 Prof. Reichert on the Phenomena of Motion 



movement. Nevertheless other observers, especially J. Muller, 

 have indicated the imperceptible mutual displacement of the 

 filaments as a phenomenon of active movement ; and the fact 

 must be admitted that such displacements of the filaments do 

 occur, in which neither the other active movements of the 

 filaments themselves nor any causes of motion in the sur- 

 rounding fluid are perceptible. It is exceedingly probable 

 that the causes lie in active movements which occur concealed 

 within the shell at the base of the filaments. 



It will be sufficient to indicate preliminarily that the pheno- 

 mena of movement referred to, and indeed, as will immediately 

 appear, also the so-called granular movement, are only to be 

 regarded as the visible effects of those changes in the substance 

 of the filaments which are produced by the so-called contrac- 

 tility. Of these changes in the material no trace can be detected 

 by the microscope either here, under apparently very favourable 

 circumstances, or in any other contractile substances; we find 

 ourselves rather only in a position to infer the existence of those 

 invisible movements which occur in the contractile substance 

 itself from the effects produced by them (which become an ex- 

 pression visible to us) in the change of form of contractile struc- 

 tures or in changes of the relative positions of the organs par- 

 ticipating in them. The supporters of the sarcode-theory have 

 certainly gone a step further by the manner in which they con- 

 ceived the granular movement. To them the apparent granule 

 is a portion of body-substance containing globules, which flows 

 out of the shell into the extended filament, and again flows back, 

 thus elongating and shortening the filament, or causing the ap- 

 pearance of lamellae and islands in the radiary complex of fila- 

 ments by the local accumulation of sarcode. In sarcode, there- 

 fore, we should succeed in seeing what has hitherto been denied 

 to us in other contractile structures. Contraction would thus 

 consist in a movement of the mass of the contractile substance, 

 in a transfer of it from one place to another far distant, and the 

 changes of form in contractile structures occur as a consequence 

 of this. In this way it becomes intelligible how the notion 

 could arise of identifying the currents of fluid in cells with the 

 currents of contraction in the pseudopodia. As it may be de- 

 monstrated that the granular movement is not produced by the 

 flowing to and fro of portions of the body-substance of the 

 Polythalamia containing globules, I am saved the trouble of 

 entering more particularly into the further consequences of this 

 conception of the contractile movements of the supposed fluid 

 sarcode and its application to other contractile structures. 



