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Carpenter, progressed in organisation since even the Laurentian epoch; for some organisms would have to remain fitted for simple conditions of life, and what could be better fitted for this end than these lowly organised Protozoa? Such objections as the above would be fatal to my view, if it included advance in organisation as a necessary contingent.
I comprehended instantly, that, by the wondrous power of my lens, I had penetrated beyond the grosser particles of aqueous matter, beyond the realms of Infusoria and Protozoa, down to the original gaseous globule, into whose luminous interior I was gazing, as into an almost boundless dome filled with a supernatural radiance. It was, however, no brilliant void into which I looked.
There is no certainly known extinct order of Protozoa; there is but one among the Coelenterata that of the rugose corals; there is none among the Mollusca; there are three, the Cystidea, Blastoidea, and Edrioasterida, among the Echinoderms; and two, the Trilobita and Eurypterida, among the Crustacea; making altogether five for the great sub-kingdom of Annulosa.
In attempting to understand the elements out of which mental phenomena are compounded, it is of the greatest importance to remember that from the protozoa to man there is nowhere a very wide gap either in structure or in behaviour. From this fact it is a highly probable inference that there is also nowhere a very wide mental gap.
It thus appeared that protozoa floating freely in the water lighted their lamps only in response to excitation, of some sort, which affected, almost instantaneously, areas many square miles in extent; while those that were attached to, or in contact with, solid matter kept their lamps lighted all the time.
A perception of the value of a review, whether friendly or hostile, is as old as St. Paul's Epistle to the Philippians. Hoodwinking the Public Sincerity or honesty is a low and very rudimentary form of virtue that is only to be found to any considerable extent among the protozoa.
This well-known and clearly demonstrated fact ought to have suggested a problem to the minds of students: How do the protozoa of malaria enter the circulatory current of the blood?
The contained protoplasm of a vegetal cell, which has self-mobility and when liberated sometimes performs amoeba-like motions for a time, may be regarded as an imprisoned amoeba; and when we pass from it to a free amoeba, which is one of the simplest types of first animals, or Protozoa, we naturally meet with kindred phenomena.
The pond in which bacteria and protozoa are living may dry up, and these organisms may be killed by the billion. Even the human species cannot be regarded as exempt from the necessity of carrying on this kind of natural strife, for scores and hundreds die every year from freezing and sunstroke and the thirsts of the desert.
There are other egg-cells, like the first, each one of which can, under favorable conditions, develop into a multicellular individual like the parent. But, 2, there are nutritive, somatic cells, which nourish and transport the germ-cells, and after their discharge die. These somatic cells, being mortal, differ altogether from the germ-cells and the protozoa.
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