98 



LUCERNARIiE AND THEIR ALLIES. 



197. The Chundroplryu {^ 69) of the mnhella {fi'js. 82, 83, c, c\ c\ c\ 106, 107, 

 109). lu the same way that the choudromyoplux stands as an elastic connective 



irraph (If 129), all Rliizopods are " moving, sentient masses of Cytoblastevia," and that alone. Here, 

 tlifii, one cannot (loul)t that cytoblastema is self-proliferous when an Amoeba grows. It is most 

 goneraily adopted as a theory that the cells, of which a wall or tissue is composed, are of primary 

 importance, not only in the adult age, but ab initio ; that it is to the cells that the wall or tissue 

 owes its existence p?(mar(7^. This seems to be the opinion of most histologists, from Schwam down 

 to Virchow and Beale. Schwam (Mikroskop. Untersuch., 1838) claims that cells crystallize out, as it 

 were, from an amorphous cytoblastema. The nucleolus, when present, originating first, and con- 

 densinf around it material for nucleus, and the latter carrying on the operation begun by the nucle- 

 olus ■ that they have a metabolic power of drawing from the cytoblastema material for development, 

 and producing chemical changes in it, while the cytoblastema itself remains passive, merely funiish- 

 ing the nutriment for these purposes. In order to account for the initial impetus be is obliged to 

 assume that the cytoblastema is heterogeneous, that it is studded with numerous points of greater 

 density than the general mass, and that at these points a tendency is exerted which draws surround- 

 ing material toward them, very much in the same way, he argues, — although he does not positively 

 insist on an identity, — that crystals are induced to form around or in certain areas of condensation. 

 This amounts, after all, and however much he may wish to make it appear otherwise, to an admis- 

 sion that the cytoblastema has within itself the originotinij power of cell-formation. And, moreover, 

 this admission is enhanced by his asserting that the cytoblastema is self-generating, i. e., proliferous, 

 and that often the nucleus is an undefined mass for a long time after the peripheric portions of the 

 cell have begun to develop ; thus divulging the fact, although unwittingly, that the area of conden- 

 sation is not precisely about, and in reference to the power of one body, but that this body, OTyiucleus, 

 is merely the gnide-post which assists the congregating particles of matter in arranging themselves 

 in symmetrical order in reference to some one lateral point in the cell. Schwam interprets it differ- 

 ently, however, and claims to have proved that the nucleolus, nucleus, and cell-membrane each 

 attracts to itself, and by its own inherent power, material which differs from that entering into the 

 ei)m])Ositiou of the others. We must quote liim, therefore, for what he claims, and not for what he 

 l)i'oves, strictly speaking. All animal tissues, in the opinion of this author, are originally cellular, 

 but a part of them cease to be so by a transformation of the cells into tubes, or fibres and fibrilliE. 

 He does not, though, go so far as his successors, and claim that a cell necessarily has a niemlirane 

 about it; on the contrary, he says that " many cells, however, do not exhibit any appearance of the 

 formation of a eell-merabrane, but they seera to be solid, and all that can be remarked is that the 

 external portion of the layer is somewhat more compact." In this respect he anticipates the theory 

 of Beale, and also of Virchow, of late. 



(R) Virchow originally, like others, demanded that a body must have a distinct wall about it in 

 order to be a cell, and denied that cells developed by free cell formation, i. e., without the interven- 

 tion of previously existing cells; his motto was rmnis cellula e celhda. He agreed with Schwam 

 that cells have a self-asserting power, and went beyond him in attempting to prove that they exer- 

 cise a control over the interstitial substance, insisting that "the intercellular substance is dependent 

 in a certain definite manner upon the cells, and tliat it is necessary to draw boundaries in it also, so 

 that certain districts belong to one cell, and certain others to another." (See Virchow, "Cellular 

 Pathology," translated by Chance ) But he also takes considerable pains to impress upon his hearers 

 that interstitial substance is not cytoblastema, and that the latter formative fluid does not exist in 

 nature ; thus taking away the very foundation of free cell formation. If, however, we are to believe 

 information which comes to us at second hand (see " Edinburgh Med. Journ.," February, 1865) Yirchow 

 "now did not regard a cell wall as an essential part of the cell, as given in cellular pathology, but 

 that a nucleus surrounded by a molecular blastema was sufficient to constitute a cell." This cer. 

 tainly looks like going back to Schwam again, and, as he makes the presence or absence of a cell- 

 membrane of no account, the cell is left in more open communication with the interstitial substance ; 

 i\\Q"cell territory'' is scarcely to be distinguished from the ee^/ proper, whose influence radiates 

 mto Its furthermost boundaries. While Schwam asserts that the interstitial substance {cytoblastema, 



