Note B — PREFATORY NOTE.

Nägeli makes his idioplasm ramify throughout the organism in unbroken continuity, much like a system of nerves in the higher animals. This idea with Nägeli was purely speculative. It was known that the protoplasm is in connection throughout the organism, but it has been proved more recently that only the somatic protoplasm is thus connected. The part in which the essential nature of the organism is contained is localized in the nucleus and hence might properly be designated as nucleoplasm, as Weismann suggests. If the idioplasm is localized in the nucleus, it cannot be continuous throughout the system, as Nägeli assumes. But this objection applies only to a detail of the theory and does not affect the fundamental conception,—that of a portion of the protoplasm which is differentiated from the rest and represents a definite molecular structure which determines the specific nature of the organism.—Trans.