of the cell is split into innumerable fine threads (or fibrils), which
are embedded in intercellular matter, and are prolonged into the
branching processes of the cell (b). One branch (a) passes into a
nerve-fibre. (From Max Schultze.))

In contrast with this very elaborate and very strictly differentiated
psychic cell (Figure 1.9), we have our ovum (Figures 1.1 and 1.2),
which has hardly any structure at all. But even in the case of the
ovum we must infer from its properties that its protoplasmic body has
a very complicated chemical composition and a fine molecular structure
which escapes our observation. This presumed molecular structure of
the plasm is now generally admitted; but it has never been seen, and,
indeed, lies far beyond the range of microscopic vision. It must not
be confused--as is often done--with the structure of the plasm (the
fibrous network, groups of granules, honey-comb, etc.) which does come
within the range of the microscope.

But when we speak of the cells as the elementary organisms, or
structural units, or "ultimate individualities," we must bear in mind
a certain restriction of the phrases. I mean, that the cells are not,
as is often supposed, the very lowest stage of organic individuality.
There are yet more elementary organisms to which I must refer
occasionally. These are what we call the "cytodes" (cytos = cell),
certain living, independent beings, consisting only of a particle of
plasson--an albuminoid substance, which is not yet differentiated into
caryoplasm and cytoplasm, but combines the properties of both. Those
remarkable beings called the monera--especially the chromacea and
bacteria--are specimens of these simple cytodes. (Compare Chapter
2.19.) To be quite accurate, then, we must say: the elementary
organism, or the ultimate individual, is found in two different