Cell and Protoplasm. 105 



in virtue of the reciprocal action of its component cells 

 is another fundamental conclusion of the cell-doctrine. 

 But it is evident that there can be no physiological 

 resting-place here, since metabolism is a chemical pro- 

 cess, and must be so expressed in the long run. The 

 life of the city is not intelligible in terms of the houses 

 merely; we must analyse down to the members of each 

 household. 



(c) Embryological Criticism. More serious perhaps 

 than either of the foregoing is the reaction from the 

 suggestion that development is to be explained in terms 

 of cell-formation. Thus Sachs says, "cell-formation is 

 a phenomenon very general, it is true, in organic life, 

 but still only of secondary importance; at all events, it 

 is merely one of the numerous expressions of the forma- 

 tive forces which reside in all matter, in the highest 

 degree, however, in organic substance". On the zoo- 

 logical side Mr. Sedgwick has forcibly expressed the 

 same view. 



"As far as plants are concerned", Prof. Wilson 

 (1896, p. 293) says, "it has been conclusively shown 

 by Hofmeister, De Bary, and Sachs, that the growth of 

 the mass is the primary f actor \ for the characteristic 

 mode of growth is often shown by the growing mass 

 before it splits up into cells, and the form of cell-division 

 adapts itself to that of the mass: Die Pflanze bildet 

 Zellen, nicht die Zelle bildet Pflanzen (De Bary)." 



It may be doubted whether the pendulum of opinion 

 has not been extreme in its reaction from the "cell- 

 standpoint". From the historical point of view, it 

 seems certain that the cell-doctrine has done more for 

 biology than any other generalization, except that of 

 evolution. It may have suggested some erroneous 

 notions, as other generalizations have, but there re- 

 mains a solid basis of fact, which may be re-interpreted, 

 but cannot be gainsaid. 



Of recent years the study of the cell, "cytology" as it 

 is called, has indeed come in as a flood, for Modern 

 almost every week has seen the publication of Analysis 

 some fairly important paper, and at times it of the Cel1 ' 

 seems difficult to find firm foothold from which to face 



