DIFFEEEN^TIATION BY SEGREGATION AND 

 ENVIRONMENT IN THE DEVELOPING 

 ORGANISM^ 



ITR. VERA DANCHAKOFF 



r>iui.(»(;i, \i, cstigations in the twentieth century have 

 markedly .sli'cii.i-thenod tiie l)elief in the specificity of 

 different kinds of Jiviiiu' matter. Palcoiitoh.uy lia- shown 

 the existence of ()r,uaniMii> wliicli liaxc retained tlicir 

 specificity during niillions of years: speeitie ,u'eriiipla>aia 

 has carried througii ag'es si>ecific. characters. On the 

 other hand discoveries in tiie world of niicroorg-anisms 

 have shown, that even tlieir simplest forms are character- 

 i/XMl if not always by s])ccific organization, at least by defi- 

 nite nietahollMM and otiier hiolo-i.-al Mnalitic- nn lii.-h imply 



1 ^liall not di^-ii^^ the prol.h-ni of -enu^ m km-I li.-ity. 

 Mn HlW.ie.-t is limile.l to the ^pe.'itieitx of crrtain li^Mies 

 and eell< found in the or-ani^m. th.' tinal (h'velopmrnl of 



or whetiier th.Te rxi^t in the oruani-m pla.tie fa<-tors 

 which from a humo-eneou:- eell material mav mould dif- 

 fcrentU or-aiii/ed pi-odu<-!^ i^ ^till uuM'tlled. TIm" solu- 

 tion of thi-^ in-ol.lem X\ould he UMvatlx adNMIlred. if the 



419 



