58 SCIENCE AND PHILOSOPHY OF THE ORGANISM 



relations Wilhelm Koux established with the aid of 

 morphogenetic experiment. 



THE WORK OF WILHELM ROUX 



We know already that an hypothesis about the founda- 

 tion of individual development was his starting-point. Like 

 Weismann he supposed that there exists a very complicated 

 structure in the germ, and that nuclear division leads to 

 the disintegration of that structure. He next tried to 

 bring forward what might be called a number of indicia 

 supporting his view. 



A close relation had been found to exist in many cases 

 between the direction of the first cleavage furrows of the 

 germ and the direction of the chief planes of symmetry 

 in the adult : the first cleavage, for instance, very often 

 corresponds to the median plane, or stands at right 

 angles to it. And in other instances, such as have been 

 worked out into the doctrine of so-called " cell-lineages," 

 typical cleavage cells were found to correspond to typical 

 organs. Was not that a strong support for a theory which 

 regarded cellular division as the principal means of 

 differentiation ? It is true, the close relations between 

 cleavage and symmetry did not exist in every case, but 

 then there had always happened some specific experimental 

 disturbances, e.g. influences of an abnormal direction of 

 gravity on account of a turning over of the egg, and it 

 was easy to reconcile such cases with the generally accepted 

 theory on the assumption of what was called "anachronism" 

 of cleavage. 



But Eoux was not satisfied with mere indicia, he 



