kim: of w a tkk 63 



WliiU li;;ht docs the sLriicLuiv thr.iw mi (he results of the preceding 



('XpClillH'Ilt '.' 



l\i:ri:iii:NCKs. Detiuer-Moor ,'.» ; (laiKHiir, 1<*. 



EXPERIMKX'I" XXXIX 



Passage of water from stem to leaf. I'lacc m fnslily cut Icafv 

 shoot of some plant with large, thin leaves, sudi as Uijili-aivini 

 Ilortensid, in eosin solution for a few minutes. As soon as tin* 

 leaves show a decided reddening pull soiiu^ of them off and 

 sketch the red stains on the scars thus made. What does tliis 

 show ? 



EXl'KKLMKXT XE 



Rise of water in leaves.* * Tut the freshly cut ends of tlu' 

 petioles of several tliin leaves of different kinds into small glasses, 

 each containing eosin solution to the depth of one quarter inch oi- 

 more. Allow them to stand for half an hour, and examine them 

 by holding up to the light and looking through tliem to see into 

 what parts the eosin solution has risen. Allow some of the leaves 

 to remain as much as twelve hours, and examine them again. 

 The red-stained portions of the leaf mark the lines along which, 

 under natural conditions, water rises into it. Cut across (near the 

 petiole or midrib ends) all the principal veins of some kind of 

 large, thin leaf. Then cut off the petiole and at once stand the 

 cut end, to which the Idade is attached, in eosin solution. Ivcpeat 

 with another leaf and stand in watei-. AVhat do the results teacli".' 



KXI'KKIMKN r XLI 



Does the leaf vary in its starch contents at different seasons? Collect in 

 early suinmer, at the close of a sunny day, some leaves of different kinds of 

 trees and shrubs and preserve them in alcohol. Collect other leaves of 

 the species as they are befjinninj; to droji from the trees in autumn and pn*- 

 .serve them in the same way. Test some of cuch lot for starch, :us de.scribtMl 

 in K.\p. XXXII. 



What does the result indicate ? 



