United States or Laos ? Vote for the TOP Country of the Week !
This was supplemented a little later by Fleming's Omnis nucleus e nucleo, when still more refined methods of observation had shown that the part of the cell which always first undergoes change preparatory to new cell-formation is the all-essential nucleus. Thus the nucleus was restored to the important position which Schwann and Schleiden had given it, but with greatly altered significance.
The limited and peculiar activity which arises in matter and which we call vital; which comes and goes; which will not stay to be analyzed; which we in vain try to reproduce in our laboratories; which is inseparable from chemistry and physics, but which is not summed up by them; which seems to use them and direct them to new ends, an entity which seems to have invaded the kingdom of inert matter at some definite time in the earth's history, and to have set up an insurgent movement there; cutting across the circuits of the mechanical and chemical forces; turning them about, pitting one against the other; availing itself of gravity, of chemical affinity, of fluids and gases, of osmosis and exosmosis, of colloids, of oxidation and hydration, and yet explicable by none of these things; clothing itself with garments of warmth and color and perfume woven from the cold, insensate elements; setting up new activities in matter; building up myriads of new unstable compounds; struggling against the tendency of the physical forces to a dead equilibrium; indeterminate, intermittent, fugitive; limited in time, limited in space; present in some worlds, absent from others; breaking up the old routine of the material forces, and instituting new currents, new tendencies; departing from the linear activities of the inorganic, and setting up the circular activities of living currents; replacing change by metamorphosis, revolution by evolution, accretion by secretion, crystallization by cell-formation, aggregation by growth; and, finally, introducing a new power into the world the mind and soul of man this wonderful, and apparently transcendental something which we call life how baffling and yet how fascinating is the inquiry into its nature and origin!
Comparative embryology reminds us at every turn that the organism dominates cell-formation, using for the same purpose one, several, or many cells, massing its material and directing its movements, and shaping its organs as if cells did not exist, or as if they existed only in complete subordination to its will, if I may so speak.
Instead of being a structure generated de novo from non-cellular substance, and disappearing as soon as its function of cell-formation was accomplished, the nucleus was now known as the central and permanent feature of every cell, indestructible while the cell lives, itself the division-product of a pre-existing nucleus, and the parent, by division of its substance, of other generations of nuclei.
All manner of schemes of cell-formation were put forward during the ensuing years by a multitude of observers, and gained currency notwithstanding Von Mohl's reiterated contention that there are really but two ways in which the formation of new cells takes place namely, "first, through division of older cells; secondly, through the formation of secondary cells lying free in the cavity of a cell."
Ehrenberg, another high authority of the time, contended that no such division occurs, and the matter was still in dispute when Schleiden came forward with his discovery of so-called free cell-formation within the parent cell, and this for a long time diverted attention from the process of division which Von Mohl had described.
It seems to the writer that +The Athenaeum+ must have misconstrued Dr. Steinach's experiments in some degree, inasmuch as it is difficult to conceive of the operation of severing a genital duct as conducive to cell-formation. However, probably ligating is meant instead of severing. But this is not the point really brought out by Mr. Day's clever article. The real point is, Is it likely that if Mr.
But in so far as they throw light on the essential idea of an organism, they may aid us in gaining a right view of our "cell republic." Says Whitman in a very interesting article on the "Inadequacy of the Cell-Theory": "That organization precedes cell-formation and regulates it, rather than the reverse, is a conclusion that forces itself upon us from many sides."
It is the Life, or the Life Force within, acting under the direction and guidance of the subconscious or subjective mind that is the agency through which this continually new cell-formation process is going on.
Word Of The Day