Page:Popular Science Monthly Volume 13.djvu/581

From Wikisource
Jump to: navigation, search
This page has been validated.
563
MONERA, AND THE PROBLEM OF LIFE.

nations, and how in one department after another we are being out-stripped by the results of better—i. e., more scientific—knowledge, the poor pittance of "elementary knowledge" asked for in Sir John Lubbock's bill is refused by a minister whose own "education" leaves much to be desired. This state of things cannot long continue, and with such advocates for the children as the Times and Mr. Forster, we may hope that next time Sir John Lubbock brings forward his bill it will meet with a happier fate.—Nature.

 

MONERA, AND THE PROBLEM OF LIFE.
By EDMUND MONTGOMERY, M. D.
II.—THE PHYSICAL PHASE OF THE PROBLEM.

LET us suppose that we have before us a living spherule of the uniform viscid material of so-called protoplasm. It is seen slowly to push forth, at some part of its circumference, a conical process; and, after a while, it is seen still more slowly to retract the same. We are here brought face to face with the initial and fundamental manifestation of one of the chief properties of life. For, what we are observing is living motion, incipient motility. How is it accomplished? What changes in the protoplasm have given rise to this duplex movement, first of protrusion, and then of recoil, on the part of a peculiar portion of the living material?

When the phenomenon is closely watched in different kinds of monera, it becomes evident that the conical projections are formed by a portion of the protoplasm, in which the bonds of cohesion are in some way being loosened; for the matter flows out into space with a certain pushing force—it liquefies and expands. This view is quickly corroborated by the unmistakable recontraction and resolidification of the material forming the projections, when retrogression is taking place. It is plain, then, that alternate expansion and contraction are the visible elements of motility.

Strange to say, biologists have as yet only realized the importance of the latter, less fundamental part of this twofold process. They have been so struck with the peculiar contractile power, with the seemingly sensitive shrinking exhibited by the living substance, that they have deemed it the most salient and characteristic manifestation of life. To convey this notion, they generally give to the protoplasm the name of contractile substance.

Now, "contractility" may be a very expressive term for the property by which the protoplasm is enabled to accomplish the second part, the retrograde half of motility; but, even thus restricted, it in-