SCIENTIFIC PROCEEDINGS 



Abstracts of Communications. 

 Ninety-second meeting. 



Schermerhorn Hall, Columbia University, May 15, lgi8. 

 President Gies in the chair. 



179 (1357) 



The dynamics of cell-division. 



By H. H. Laughlin (by invitation) . 



[From the Eugenics Record Office.] 



From the structural point of view mitosis is a process by which 

 a living cell, through continuous and orderly transformations, 

 divides so that (a) in equational division each daughter cell dup- 

 licates the mother cell exactly at the latter's comparable stage of 

 existence; or (b) in ontogenetic division each daughter cell dupli- 

 cates the mother cell at the latter's comparable stage of existence, 

 exactly in chromatin content, but not necessarily exactly in any 

 other detail. 



From the dynamical point of view mitosis is a process related 

 and characterized as follows: Beginning in a single living cell at 

 a stage of high metabolic activity but of divisional stability thence 

 continuing by means of metabolism to a condition of low metabolic 

 activity and divisional instability the mitotic potential is estab- 

 lished. Thence reactions still proceed by virtue of the cell's self- 

 contained structural and chemical organization, and its environ- 

 mental complex. These successive reactions are so timed, localized, 

 and successively interdependent upon their preceding and adjacent 

 activities, that in equational division mitotic stability and meta- 

 bolic activity are again achieved only when this self-contained 



