132 THE RATE OF GROWTH [ch. 



This very important, and perhaps even fundamental pheno- 

 menon of growth would seem to have been first recognised by 

 Professor Chodat of Geneva, as we are told by his pupil Monnier *. 

 "On peut bien, ainsi que M. Chodat I'a propose, considerer 

 I'accroissement comme une reaction chimique complexe, dans 

 laquelle le catalysateur est la cellule vivante, et les corps en 

 presence sont Teau, les sels, et I'acide carbonique." 



Very soon afterwards a similar suggestion was made by Loebt, 

 in connection with the synthesis of nuclein or nuclear protoplasm ; 

 for he remarked that, as in an autocatalysed chemical reaction, 

 the velocity of the synthesis increases during the initial stage of 

 cell-division in proportion to the amount of nuclear matter already 

 synthesised. In other words, one of the products of the reaction, 

 i.e. one of the constituents of the nucleus, accelerates the pro- 

 duction of nuclear from cytoplasmic material. 



The phenomenon of autocatalysis is by no means confined to 

 living or protoplasmic chemistry, but at the same time it is 

 characteristically, and apparently constantly, associated therewith. 

 And it would seem that to it we may ascribe a considerable part 

 of the difference between the growth of the organism and the 

 simpler growth of the crystal J : the fact, for instance, that the cell 

 can grow in a very low concentration of its nutritive solution, 

 while the crystal grows only in a supersaturated one ; and the 

 fundamental fact that the nutritive solution need only contain 

 the more or less raw materials of the complex constituents of the 

 cell, while the crystal grows only in a solution of its own actual 

 substance § . 



As F. F. Blackman has pointed out, the multiplication of an 

 organism, for instance the prodigiously rapid increase of a bacterium, 



* Monnier, A., Les matieres minerales, et la loi d'accroissement des Vegetaux, 

 Publ. de Vlnst. de Bot. de VUniv. de, Geneve (7), in, 1905. Cf. Robertson, On the 

 Normal Rate of Growth of an Individual, and its Biochemical Significance, Arch, 

 f. Entw. Mech. xxv, pp. 581-614, xxvi, pp. 108-118, 1908; Wolfgang Ostwald, 

 Die zeitlichen Eigenschafien der Eniwickelungsvonjdnge, 1908; Hatai, S., Interpreta- 

 tion of Growth-curves from a Dynamical Standpoint, Anat. Record, v, p. 373, 

 1911. 



t Biochem. Zeitschr. n. 1906, p. 34. 



J Even a crystal may be said, in a sense, to display "autocatalysis": for the 

 bigger its surface becomes, the more rapidly does the mass go on increasing. 



§ Cf. Loeb, The Stimulation of Growth, Science, May 14, 1915. 



