1899] A NOTE ON INHERITANCE 395 
do with the conditions of development, and not with the strict problem 
of heredity. Nor is the necessity for such investigations by any means 
a new discovery, for many years have passed since Professor His pro- 
tested that “to think that heredity will build up organic beings without 
mechanical means is a piece of unscientific mysticism.” 
The Cell as a Unit of Organisation. 
THE view has often been expressed that the functions of a cell depend 
upon the mutual relations of its component parts. That is to say, 
there is a “cell-firm,” in which the most important partners are the 
nucleoplasm, the cytoplasm, and the centrosomes, a firm which owes 
its power and its success to the mutualism of its partners. Dr. F. 
Schenck has recently published an interesting paper discussing this 
conception (“ Physiologische Charakteristik der Zelle,” pp. vi.+123. 
Wiirzburg: <A. Stuber (C. Kabitzch), 1899. Price 3 marks), in 
which he comes to the following conclusions :— 
Not every cell can be called a physiological individual, such as a 
Protozoon is, for there are cells which are merely parts of a physio- 
logical individual. The process of vital combustion, and what directly 
depends on this, cannot be regarded as dependent on the co-operation 
of the characteristic components of the “cell-firm,’ and to a certain 
degree even assimilation is independent of the particular organisation. 
The latter is, however, implied in growth, regeneration, and differentia- 
tion ; in these processes the components of the cell combine to form a 
unit of organisation. But sometimes the result cannot be explained 
from within the cell itself, but depends upon the physiological relations 
between the cell and the larger system of which it forms a part. The 
cell-structure of an organism is the structural expression of a functional 
division of labour in which the nucleus plays the more important 
(organising) réle, while the cytoplasm is its medium reacting to 
external stimuli. Processes of division, in which the third important 
partner—the centrosome—has an influential réle, have for their end 
the distribution of nucleoplasm and cytoplasm in such proportions that 
appropriate cellular functions continue. There is nothing novel or 
startling in these conclusions, but they are temperately expressed and 
illustrated in considerable detail; and we can heartily commend the 
publication to those particularly interested in cell-problems. 
