CELL-FORMATION.
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by a membrane; the other is where the contents of acell become detached from the walls only in places, andproduce new membrane on these places. One extremeis a perfect cell-formation ; the other merely a slightalteration of the form of the cell, combined with a partialproduction of new membrane. One extreme is the pro-duction of a new individual cell; the other is the re-organization of the partially injured individuality.
Between the two extremes occur a quantity of inter-mediate stages, in which it is doubtful, in particularcases, whether the old cell persists in an altered form, orwhether a new cell has replaced it. The fact is certain,but the explanation is furnished by the observer. In allthose cases where the mucilaginous layer is merely de-tached in places from the cell-wall, and produces piecesof membrane, we always recognize the cell as the same,with partially altered form and membrane. In all thosewhere portions of the contents become isolated, andcomplete their separation from one another by the forma-tion of membrane, we suppose new cells to take the placeof the parent-cell; but if the entire contents of a cell aredetached from the wall, become isolated, and then forma new complete membrane, we may call this a cell-forma-tion, as well as we can call it formation of membrane.The contents of the old and new cell are exactly the same,the walls altogether different. Is a new individualformed, or is the individual merely reorganized (throughregeneration of an organ) ? This case stands just mid-way, and admits either explanation equally well. A steptoward one side (if not the whole contents, but merely aportion, become detached from the wall), or one steptoward the other (if not the whole contents, but merelya portion of them become completely isolated), will strictlydecide the explanation to be either reorganization of thecell, or cell-formation.
The transition occurs again in a different way. If thecontents of a cell become detached from the wall in oneplace, and acquire a new coat of membrane over this
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