28 MORPHOGENESIS IN CILIATES 



orderly function of the total population are predicated on 

 the presence of all essential members in definite concentra- 

 tions, combinations, and distributions." 



It is clear also that kinetosomes need some food not only 

 to live but also to grow and to multiply, and probably some 

 specific food. It has been noted that, at certain phases of 

 the life cycle, kinetosomes of one region multiply whereas 

 others do not. The specific food must therefore be con- 

 centrated in certain areas. We may quote here another of 

 Weiss's conclusions: "If the specific existential and opera- 

 tional prerequisites for the various molecular species and 

 groups differ at different sites of the cell, different species 

 will automatically become segregated into their appropriate 

 ecological environments. As a result, even a wholly in- 

 discriminate mixture can become sorted out into a definite 

 space pattern." 



It seems plausible to admit that localization of specific 

 molecules is controlled by their affinities for some differenti- 

 ated parts of the cortex or, in the last analysis, by the 

 properties of the given molecule and of the cortex. The hy- 

 pothesis cannot of course be excluded that these specific 

 substances are formed only in some areas owing to the dis- 

 tribution of some specific enzymes. 



The granules of anarchic fields may become oriented in 

 longitudinal rows. They are evidently submitted to some 

 mysterious and powerful field of forces. 



Proposition 6 of Paul Weiss (1947) fits very well with 

 this hypothesis: "Organization in space of the content of 

 the cell, and of any of its constituent particulate elements 

 as well, therefore, presupposes a primordial system of spa- 

 tially organized ^conditions' to set the frame for the later 

 differential settlement of different members of the dispersed 

 molecular populations." 



When we look upon the whole series of changes which 

 take place throughout the life cycle between the rows 7 and 



