^o nL4.\SFORMAriOy OF EXERGY 



at an angle of 135*= with the vertical and pointing upwards, i. e. 45^ above the 

 horizantaL [Several antborities, FrrrrsG (1905) especially, have shown that 

 the optimiim stimnhis is given in the horizontal position.] In both types of 

 organ, however, it mav be determined that in addition to the normal position 

 the inverse positicm is also a ptKitionof rest; certainly roots bend downwards 

 in a short time wiien inverted and shoots upwards. 



These reactJcms are, however, cxxiseqnent on small curvatures induced 

 by internal factors^ by which a deviatitm from the position ot rest is brought 

 about. If a plant tinned upside down be mechanically prevented from per- 

 locmiDg any antooomoos c m \ a lur e a geotropic curvature never takes place as an 

 after-effect <hi the Jdinostat. There is always one noticeable diffo-ence between 

 the two positions of rest, the normal position is stable but the inverted ptKJtion 

 B labile. Any organ which is inclined somewhat from tir ir. : r position 

 does not bend back again into that positicxi but attempts to assM" t : t r. ormal 

 direction. The only point we have to deal with here is :r ^ — ir Errcr^cc of the 

 stable into the labfle postticHi, and \\ce versa : we have c : - er the end by 



in 2. — ; "i '- "^ - " ' " jfct* 



Vig. I jSl T«o floats otf /fa M " * y - ftsesl hi 



which tl- -- - - 7-'^: XoLL, 1892). I: : ^nploy isolated 



branche ' their apices th- :-.::.' which takes 



jdaoeis ::^ -uz:- _- :. ^ - ^^ -.his fixed in the normal position, 



that -3 growth accekiation, but the 



fort:- .. .-- .ends upmards and reaches the 



s&idl: -i lie (T\s. 136). 



At- curvature foUows when the plant 



• --- "' t: described as positions of rest, 



r^ect of gravity cm the plant ? 



: years show more and more 



'jvement a whole 



'"• ''rominent 



ent affect 



-nt. Under such circumstances at 



— '--A; (I) the appreciation or 



t organ; (2) the reaction of 



