Chap. XL TRANSMITTED EFFECTS : VIOIA. 



527 



former trial; and after their tips (1-5 mm. in length) had been 

 ainputated, they were placed vertically in damp peat. Of these, 

 three were not in the least affected and continued for days to 

 grow straight downwards. Four showed after 8 h 30 m. a mere 

 trace of curvature in the direction in which they had been acted 

 on by geotropism; and in this respect they differed much from 

 those which had been exposed for 

 1 h. 37 m., for many of the latter 

 were plainly curved in 6 h. The 

 curvature of one of these four 

 radicles almost disappeared after 

 24 h. In the second, the cur- 

 vature increased diwing two days 

 and then decreased. The third 

 radicle became permanently bent, 

 so that its terminal part made an 

 angle of about 45° with its original 

 vertical direction. The fourth 

 radicle became horizontal. These 

 two latter radicles continued 

 during two more days to grow 

 in the peat io the same directions, 

 that is, at an angle of 45° be- 

 neath the horizon and horizon- 

 tally. By the fourth morning new 

 tips had been re-formed, and now 

 geotropism was able to act on 

 them again, and they became 

 bent perpeudiciTlarly downwards, 

 exactly as in the case of the 

 five radicles described in the 

 last paragraph and as is shown in 

 the figure (Fig 195) here given. 



Lastly, five other radicles were similarly treated, but were ex- 

 posed to geotropism during only 45 m. After 8 h. 30 m. only 

 one was doubtfully affected; after 24 h. two were ju.st per- 

 ceptibly curved towards the side which had bee.i acted on by 

 geotropism ; after 48 h. the one first mentioned had a radius of 

 curvature of 60 mm. That this curvature was duo to the a( tion 

 of geotropism during the horizontal position of the radicle, waa 

 shown after 4 days, when a new tip had b^en reformed, for it 

 then grew perpendicularly downwards. We learu from this 



Vioia faha : r.idicle, rectangularly 

 bent at A, after the umpu'ation 

 of the tip, due to the previous 

 influence of geotropism. L, side 

 of bean which lay on the peat, 

 whilst geotropism acted on the 

 radicle. A, point of chief cur- 

 vature of the radicle, whilst 

 standing vertically downwards. 

 B, point of chief curvature after 

 the regeneration of the tip, when 

 geotropism again acted. C, re- 

 generated tip. 



