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 certain, sooner or later, to disappear. There is therefore no real cell without a nucleus, any more than there is a nucleus without a cell. The exceptions to this law are only apparent. Histologists have examined them one by one, and have shown their purely specious character. We may therefore lay aside, subject to possible appeal from this decision, organisms such as Haeckel's monera and the problem of finding out if bacteria really have a nucleus. The very great, if not the absolute generality of the nuclear body, must be admitted.

It hence follows that there is a nuclear protoplasm and a nuclear juice, just as we have seen that there is a protoplasm and a cellular juice. What was just said of the one may now be repeated of the other, and perhaps with even more emphasis. The nuclear protoplasm is a filamentary mass sometimes formed of a single mitome or cord, folded over on itself and capable of being unrolled. The mitome in its turn is a string of microsomes united by the cement of the linin. These are the same constituent elements as before, and the language of science distinguishes them one from the other by a prefix to their name of the words cyto or karyo, which in Greek signify cell and nucleus, according as they belong to one or the other of these organs. These are mere matters of nomenclature, but we know that in the descriptive sciences such matters are not of minor importance.

We have just indicated that in a state of repose,—that is to say, under ordinary conditions,—the structure of a nucleus reproduces clearly the structure of the cellular protoplasm which surrounds it. The nuclear essence is best separated from the spongioplasm. It takes more clearly the form of a filamentary