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It includes the phenomena of conjugation and fertilization among both unicellular and multicellular organisms. ANABOLISM. See METABOLISM. ANAMNESIC. Pertaining to or aiding recollection. ANEMIC. Deficient in blood; bloodless. ANTHROPOMORPHISM. The attributing of human characteristics to natural, supernatural, or divine beings. ANTHROPOMETRY. Science of measurement of the human body.

The gastraea theory has now convinced us that all the Metazoa or multicellular animals can be traced to a common stem-form, the Gastraea. In accordance with the biogenetic law, we find solid proof of this in the fact that the two-layered embryos of all the Metazoa can be reduced to a primitive common type, the gastrula.

Can we conceive of an indestructible thing be it unicellular or multicellular, alive or robotic, composed of independent individuals or acting in perfect, centrally-dictated unison? Can anything be, in principle, eternal? This question is not as outlandish as it sounds. By fighting disease and trying to postpone death, for instance, we aspire to immortality and imperishability.

From coenobia or social unions of these afterwards arose the lowest histones, multicellular plants and animals. By the sure help of the three great empirical "records of creation," palaeontology, comparative anatomy, and ontogeny, the history of descent now leads us on step by step from the oldest Metazoa, the simplest pluricellular animals, up to man.

But a second principle in this growth of the machine was needed to produce the variety which is found in nature. As the different cells in the multicellular mass became associated into groups for different duties, the method of such division of labor was not alike in all machines.

PLANTS. No remains of plants have been found in Cambrian strata, except some doubtful markings, as of seaweed. SPONGES. The sponges, the lowest of the multicellular animals, were represented by several orders. Their fossils are recognized by the siliceous spicules, which, as in modern sponges, either were scattered through a mass of horny fibers or were connected in a flinty framework.

The organs of the first kind represent the CONSERVATIVE element in the multicellular state of the human frame, while the latter represent the PROGRESSIVE element. The course of historic development is a result of the correlation of the two tendencies, and they must be carefully distinguished.

There is no variation during geologic time of these primordial living organisms. All conceivable changes of environment have passed over them, but they change not. Bacteria struggle together, one form devouring another form. Unicellular life long precedes multicellular.

Now, if I pass from the top to the bottom of the scale of living beings, from one of the most to one of the least differentiated, from the multicellular organism of man to the unicellular organism of the Infusorian, I find, even in this simple cell, the same process of growing old.

But we must proceed to examine the behavior of the various kinds of cells of which the various multicellular organisms are composed. Plants were known to be composed of cells, and their cells were studied and described some years before it was understood that animals also are composed of cells as units.