C(intrlfi((/(il Force ini I'hiiils. 145 



r;itlirr (Iclic.-ilc iil;iiils of lliis kind (•;iii sImikI and liiially i-('co\cr. This lliey 

 (lid. wlii'ii iiiiiuU'd, in jiIm.iiI two \vcci<s so (luit a( llie cxpinilioii of liuiL lime 

 nn diffcrcucc was visililc liclwccii the cxiKTiinciital and tiic controj i»iants 

 as soon above f,'roun(l in tlio jjrowtli of tlio stem. In many cases the growth 

 of lateral roots nml;os a very proIoM^iod cxporiment impracticable. In each 

 case when the roots won- niailscd olT in tlio nsnal way to .show the growing,' 

 rouion w^hose yrowtli was iossonod as shown by coniimrison the growth 

 was not completely stojipod in any zone, other than that the growth was 

 (locreased in the growing zones the regions and relation of growth to the 

 controls remained the same. Many more experiments have been made on 

 other plants which conhrm those points. The centrifugal force therefore 

 used by Schwartz and Kiting and others did not cause a noticeable dilfer- 

 onc(> simply because it was not of sulliciont intensity. In all the experiments 

 which I performed the contents of all the cells was thrown to the centrifugal 

 end of the cell. It returned to its normal postion in the various cells 

 whether they were large or small after two to three days. Even after 

 the contents had returned to its normal position, as indicated above, a much 

 longer time was still necessary to allow the complete shock of the centrif- 

 ugal force to disappear. This varied according to the plant and the intens- 

 ity of the centrifugal force. 



