Causation of Vital Movement 



429 



activity, and if Morphology, " since it has made the arising of form 

 more its study than the describing of what is already completed," has 

 become part of Physiology, it might be possible and conceivable that 

 research directed to all activities and going beyond the visible form 

 to the chemical components of the structures and the transformation 

 of substance and force, should observe great differences in processes 

 where all our morphological experience would only have shown 

 identity. We were near enough to this point ; for if it were true, as 

 was long assumed, that that which is the bearer and the seat of the 

 most essential of all vital processes in the cell is completely form- 

 less, it is not easy to see why the form should be so determinant of 

 function. 



We have hope that this is not so, and will endeavour to show in 

 Movement the functional as well as the morphological unity of all 

 living matter. 



As I have already said, there is an elementary kind of movement 

 in the cell, carried out by the cell-body — that part of the cell which 

 in contradistinction to nucleus, membranes, and various enclosures, 

 has been designated protoplasm. The protoplasm moves itself, as in 

 the case of certain free-living Protozoa, like the long-known Amoeba, 

 like the so-called Sarcode — in many cases better comparable to the 

 movement of the pseudopodia of Rhizopods. The resemblance of the 

 latter to what was formerly called the sap-current in many plant-cells, 

 led Ferd. Cohn (2) to interpret plant protoplasm as sarcode, an idea 

 actively supported by Max Schultze (3), the best authority on pseudo- 

 podial movement. It is not necessary to say here how widespread 

 protoplasmic movement is, for there cannot be a cell that does not 

 present it at some stage of its existence. Doubt on this subject can 

 only exist in regard to the smallest of all organisms, those of fermen- 

 tation, of putrefaction, and of pathogenic activity which are too small 

 for observation. But even in these, from the movement they perform 

 as a whole, we have grounds to infer the existence of a protoplasm. 



It is proved that protoplasmic movement does not follow external 

 impulses or currents, but is a spontaneous activity. It may go on in 

 opposition to gravity, and overcomes frictional resistance, as shown 

 by the mass itself moving forward on surfaces of every kind, and 

 being able to drag heavy bodies along with it. It is proper mecha- 

 nical work. 



The cause of the movement can only be an internal one, residing in 

 the contractile substance itself, and can only consist of chemical pro- 

 cesses taking place within the peculiar pasty, slime-like mass. Yet the 

 question had to be put whether these processes were not first set up 

 by something coming perhaps from the outside, for the movement 

 changes, sometimes stops or takes place more slowly, or occurs but par- 

 tially, and may by many means be artificially aroused or diminished. 



