EFINITE NOTIONS REGARDING THE FUNCTION OF THE IDIOPLASM.

A plasmic substance causes definite chemical and physical changes only
when it is present in a certain condition of motion. The peculiar agency
which the idioplasm has in each ontogenetic stage of development and in
each part of the organism depends on the activity of a definite group of
micellae in the cross section of the strand or of a complex of such
groups, while this local stimulus controls the chemical and physical
processes by dynamic influence and by transmission of a specific mode of
motion, even to a microscopically small distance.

The effective stimulus in a plasmic substance is dependent on its own
nature and the influence which it receives from without. Which group of
micellae in the idioplasm receives the stimulus depends on the
configuration, on the preceding stimuli and on the position in the
individual organism in which the idioplasm is found. The determinants
have arisen one after another during the whole period of evolution from
the primordial cell. The configuration of the idioplasm is a character
of phylogeny and the determinants in it have by nature the tendency to
develop in the order in which they were formed. Further, since the
ontogeny begins as a unicellular organism with the formation of a germ
cell, that determinant of the idioplasm comes first to development,
which has developed in the unicellular ancestor. Just so the succeeding
stages of ontogeny depend for the time being on the development of the
determinants having their origin in the corresponding stage of
phylogeny. Both causes acting together--the phylogenetic configuration
of the idioplasm and the successive morphological stages of development
of the individual conditioned on it--necessarily result in the ontogeny
being the repetition of the phylogeny.

If the whole remaining line of idioplasmic determinants in an ontogeny
has reached development, the development of the germ-forming
determinants finally follows as well from the configuration of the
idioplasm as from the nature of the organism. The individual is capable
of reproduction and the new ontogenies begin in the reproductive cells.

10. TRANSMISSION OF IDIOPLASMIC DETERMINANTS IN LOCAL VARIATION AND IN
FECUNDATION.

The automatic progressive or perfecting transformation of the idioplasm
is probably active in all stages of development, and proceeds regularly
in all parts of the organism, because the idioplasm p