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 lie 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) role, while the cytoplasm is its medium reacting to 

 external stimuli. Processes of division, in which the third important 

 partner — the centrosome — has an influential role, 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 heartilv commend the 

 publication to those particularly interested in cell-problems. 



