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The nucleated cells found connected with the cancellated structure of the bones, which I first pointed out and had figured in 1847, and have shown yearly from that time to the present, and the fossa masseterica, a shallow concavity on the ramus of the lower jaw, for the lodgment of the masseter muscle, which acquires significance when examined by the side of the deep cavity on the corresponding part in some carnivora to which it answers, may perhaps be claimed as deserving attention.
The investigation of the minutiae of organic structure by the microscope is of such recent origin, that its results cannot be expected to be very clear. Some facts, however, are worthy of attention with regard to the present inquiry. It is ascertained that the basis of all vegetable and animal substances consists of nucleated cells; that is, cells having granules within them.
When we carry back the analysis of an organized body as far as we can, we find every part of it made up of masses of nucleated protoplasm of various sizes and shapes. In all essential features these masses conform to the type of protoplasmic matter just described. Such bodies are called cells.
Traced back to its earliest state, the nettle arises as the man does, in a particle of nucleated protoplasm. And in the lowest plants, as in the lowest animals, a single mass of such protoplasm may constitute the whole plant, or the protoplasm may exist without a nucleus.
But, as it is admittedly impossible to draw any distinct boundary line between this no man's land and the vegetable world on the one hand, or the animal on the other, it appears to me that this proceeding merely doubles the difficulty which, before, was single. Protoplasm, simple or nucleated, is the formal basis of all life.
And it is not doubted that, if the conditions of the universe brought about a natural combination of carbon, hydrogen, nitrogen and oxygen in certain proportions, so that proteid resulted, the transition to proteid which forms itself and renews itself from the surrounding elements, to assimilating, growing, dividing proteid, and ultimately to the most primitive plasmic structure, to non-nucleated, nucleated, and finally fully formed cells, could also come about.
Harold came to believe, vaguely at first but more definitely as the evidence nucleated, that Stephen's act was due to some mad girlish wish to test her own theory; to prove to herself the correctness of her own reasoning, the fixity of her own purpose.
We have already seen that this nucleated vesicle is itself a type of mature and independent being in the infusory animalcules, as well as the starting point of the foetal progress of every higher individual in creation, both animal and vegetable.
In brief, then, a cell is a mass of nucleated protoplasm; the nucleus may have a nucleolus, and the cell may be limited by a cell wall. Every tissue of the human body is formed through the agency of protoplasmic cells, although in most cases the changes they undergo are so great that little evidence remains of their existence.
To find that mosses, grasses, turnips, oaks, worms, and flies, mites and elephants, infusoria and whales, tadpoles of to-day and venerable saurians, truffles and men, are all equally the lineal descendants of the same aboriginal common ancestor, perhaps of the nucleated cell of some primaeval fungus, which alone possessed the distinguishing honour of being the "one primordial form into which life was first breathed by the Creator " this, to say the least of it, is no common discovery no very expected conclusion.
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