The idea was expressed by LOEB *) in 1906 that some of the 

 phenomena acompanying the early stages of development suggest 

 'that gr.o/w-i^ .tpayl be determined by an autocatalysed chemical reaction. 

 He,, is jnclined to. believe that cell division in the developing egg 

 ceases wBen: jfo-.^'atio of nuclear to cytoplasmic material reaches a 

 certain limit, and expresses the belief that This ratio is determined 

 by the laws of mass action and equilibrium . Following up this 

 idea, ROBERTSON 2 ) and OSTWALD S ) published almost simultaneously 

 in 1908 their investigations showing the great similarity between growth 

 curves and the curves expressing the relationship between time and 

 amount of transformation in a monomolecular autocatalytic reaction. 



The work of numerous investigators has rendered available a 

 large amount of data upon the growth of plants and animals of 

 various species. Especially accurate data upon the growth of man 

 have been accumulated by the British Association Anthropometric 

 Committee and by QUETELET in Belgium. It was these data in ad- 

 dition to those published by DONALDSON 4 ) upon the growth of rats 

 which ROBERTSON 5 ) chiefly utilized in illustrating his thesis. 



*) J. LOEB, >Dynamics of Living Matter.* New York 1906. p. 56 et seq. 



2) T. B. ROBERTSON, Arch. f. Entw.-Mech. Bd. 25. 1908. 



3 ) Wo. OSTWALD, Uber die zeitlichen Eigenschaften der Entwicklungsvor- 

 g'ange.* Vortrage u. Aufs. iiber Entwicklungsmech. d. Organismen, herausgeg. 

 von WILH. Roux. Heft 5. Juli 1908. 



4 ) DONALDSON, BOAS Memorial Volume. New York 1906. p. 5. 



5) T. B. ROBERTSON, Joe. cit. 



