318 Prof. M. Schultze on the Organization 



many cells, especially young- motile cells (I may recall the motile 

 cells of the blood described by Lieberkiihn). In the case cited, 

 llemak has explained the projection of the hyaline substance as 

 the casting of a membrane; but on this point I cannot agree 

 with that respected observer. 



But if several or many cells have come together for the for- 

 mation of the body of a Rhizopod, as we have intimated to be 

 by no means improbable (as vi^ould be the case if the body of 

 the Rhizopod were produced from an egg-cell, dividing in the 

 manner of an egg undergoing the process of segmentation), we 

 should have, according to our new protoplasm-theory, to prove 

 the following possibility with regard to the further behaviour of 

 the cells. I again remind the reader that the definition of the 

 cell given by me runs — " a naked mass of protoplasm with a 

 nucleus,^' and that I regard the membrane as something quite 

 unnecessary to the idea of a cell. There is consequently an 

 aggregation of small cells given, from which a Hhizopod-body is 

 to be formed. Then only the peripheral cells require to coalesce 

 in order to form the so-called sarcode, — the protoplasm, no longer 

 capable of resolution into cells, surrounding the internal part of 

 the body like a stratum of fluid wax.. But towards the centre 

 the individuality of the cells may maintain itself in gradual 

 transition ; they may acquire a membrane, and form tissues of 

 various kinds, as they are produced from the segmentation-cells 

 of the egg of one of the higher animals ; nay, the theory permits 

 the assumption that a heart, blood-vessels, intestine, kidneys, 

 brain and nerves — in short, whatever we please — may act in full 

 development in the interioi", whilst externally the simplest form 

 of vitalizable substance persists, and therefore the whole or- 

 ganism, complicated as it is, rolls about like an jEthalium 

 upon a heap of stinking tan. In order that a combination of 

 the highest and lowest organization so horrible in its con- 

 sequences may not occupy a place in nature, the limits of type 

 have been established. We are still far from understanding the 

 type of the Protozoa sufficiently to enable us to say, " so far, 

 and no further, may the diflPerentiation of the systems of organs 

 advance in them ;" but that they have a certain, and very definite, 

 low limit may be concluded from the analogy of the other types. 



Thus, therefore, within the Protozoan type there may easily be 

 developed from the simplest animal forms, consisting only of the 

 protoplasm of a single cell, other higher forms, in which a 

 certain or tolerably perfect degree of independence of individual 

 constituent cells exists, and indications of definite systems of 

 organs occur. But in all Protozoa (and this I would regard as 

 characteristic) there prevails in certain regions of the body, and 

 for the purpose of fulfilling certain functions, the tendency of 



