344 FORM AND STRUCTURE OF THE CELL [ch. 



the entire multicellular organism : as Schwann said of old, in very- 

 precise and adequate words, "the whole organism subsists only by 

 means of the recijpTocal action of the single elementary parts*." As 

 Wilson says again, "the physiological autonomy of the individual 

 cell falls into the background . . . and the apparently composite 

 character which the multicellular organism may exhibit is owing to 

 a secondary distribution of its energies among local centres of 

 action!." I* is here that the homology breaks down which is so 

 often drawn, and overdrawn, between the unicellular organism and 

 the individual cell of the metazoonj. 



Whitman, Adam Sedgwick §, and others have lost no opportunity 

 of warning us against a too hteral acceptation of the cell-theory, 

 against the view that the multicellular organism is a colony (or, as 

 Haeckel called it, in the case of the plant, a "republic") of inde- 

 pendent units of Ufe||. As Goethe said long ago, "Das lebendige 

 ist zwar in Elemente zerlegt, aber man kann es aus diesen nicht 

 wieder zusammenstellen und beleben " ; the dictum of the Cellular- 

 pathologie being just the opposite, "Jedes Thier erscheint als cine 

 Summe vitaler Einheiten, von denen jede den vollen Charakter des 

 Lebens an sich trdgt." 



Hofmeister and Sachs have taught us that in the plant the growth 



♦ Theory of Cells, p. 191. 



t The Cell in Development, etc., p. 59; cf. 3rd ed. (1925), p. 102.- 



X E.g. Brticke, Elementarorganismen, p. 387: "Wir miissen in der Zelle einen 

 kleinen Thierleib sehen, und diirfen die Analogien, welche zwischen ihr und den 

 kleinsten Thierformen existiren, niemals aus den Augen lassen." 



§ C. 0. Whitman, The inadequacy of the cell-theory, Journ. Morphol. viii, 

 pp. 639-658, 1893; A. Sedgwick, On the inadequacy of the cellular theory of 

 development, Q.J. M.S. xxxvii, pp. 87-101, 1895; xxxviii, pp. 331-337, 1896. 

 Cf. G. C. Bourne, ibid, xxxviii, pp. 137-174, 1896; Clifford Dobell, The principles 

 of Protistology, Arch. f. Protistenk. xxiii, p. 270, 1911. 



II Cf. 0. Hertwig, Die Zelle und die Gewebe, 1893, p. 1: "Die Zellen, in welche 

 der Anatom die pflanzlichen und thierischen Organismen zerlegt, sind die Trager 

 der Lebensfunktionen ; sie sind, wie Virchow sich ausgedruckt hat, die 'Lebensein- 

 heiten.' Von diesem Gesichtspunkt aus betrachtet, erscheint der Gesammtlebens- 

 prozess eines zusammengesetzten Organismus nichts Anderes zu sein als das hochst 

 yerwickelte Resultat der einzelnen Lebensprozesse seiner zahlreichen, verschieden 

 functionirenden Zellen." But in 1920 Doncaster (Cytology, p. 1) declared that "the 

 old idea of discrete and independent cells is almost abandoned," and that the 

 word cell was coming to be used "rather as a convenient descriptive term than 

 as denoting a fundamental concept of biology"; and James Gray {Experimental 

 Cytology, p. 2) said, in 1931, that "we must be careful to avoid any tacit assumption 

 that the cell is a natural, or even legitimate, unit of life and function." 



