92 Mr G. F. Scott Elliot on the [sess. li. 



vessels. No one supposes that water is ever entirely absent 

 from the vessels. 



There are also some anatomical objections to the view of 

 Sachs. Sachs acknowledged that in some Monocotyledons 

 and Dicotyledons, there is not enough lignilied tissue in the 

 bundles to conduct the water, and suggested that as sclereu- 

 chyma resembles true wood, it probably conducts the water to 

 some extent in its walls. This, however, is not the case. Elf- 

 ving (10) tested this view with the stem of Chamcedorea. He 

 covered the section of the stem with paraffin, and then 

 removed this paraffin first from the peripheral sclcrenchyma, 

 in which case no water passed through (even with a pressure 

 of 120 cm. Hg.), then from the vessels, and found that water 

 passed through abundantly. 



Moreover, liussow (6) pointed out that in that part of the 

 haulm of grasses which is protected by the leaf there is 

 practically no lignified or sclerenchymatous tissue at all, and 

 the water certainly travels through it. 



There are also other objections. First, on Sachs' view 

 there is no known reason why the water travelling in the 

 wood walls should not pass with equal ease in every direc- 

 tion. Elfving (10) and Boehm (5), however, found that it is 

 quite easy to force water through pieces of coniferous wood 

 cut tangentially, and impossible to force it through pieces 

 cut in the radial direction. As the disc thickenings are on 

 the radial walls only, this is what one would expect if the 

 water travels by the luniina. 



The method of causing the roots or cut surfaces of plants 

 to suck up C(jloured solutions has been very largely used (e.g., 

 La Baisse, in 1733 ; Keichel, in 1758 ; and Herbert Spencer 

 (14), in 18GG). The substances used arc very different. 

 Professor MacNal) (15) (see Transactions of this Society), 

 used blljiiiiu salts. Van 'J'icghem (16) used either fuchsin 

 or a double treatment — first with potassium cyanide, then 

 with ferrous sulphate. 'I'he liest substance, however, appears 

 to be eosin, — Darwin iiiid I'liillips (17). 



Sachs himself used this method, but considers it unsatis- 

 factory, as the salt may not travel as rapidly as the water. 

 He uses, however, an ideiiLical uuiLhod — viz., n()n-})assage of 

 cinnabar parti('les, to show that coniferous cells are not in 

 open communication for water. Van Tieghem ignores Sachs' 



