344 Transactions of the Canadian Institute. [Vol, VII. 



at the ■' top," and also one bud. These roots, strange to say, were 

 longer than those in the jar at the "butt" of the twig. 



To test if water might enter through the bark, an experiment was 

 arranged as shown in Fig. i6, 6, and left from March 14th to April 23rd 

 (forty days). One internode of the twig was kept in water, while both 

 adjacent nodes and the free ends were in the air. Absolutely no growth 

 occurred and the twig dried and shrivelled up at both ends. The 

 middle which was constantly in water shrivelled up considerably. 



From all these sets of experiments, varied as they are, some rather 

 important general conclusions may fairly be drawn. The nutrient 

 solution when applied to developing buds of the wnllow seemed to affect 

 the development of the roots of the twig in the same wa}' as when 

 applied to the place of origin of the roots. It also affected developing 

 buds, other than those immersed in it in the same way as they were 

 affected when the roots were in the liquid. All these results point 

 towards absorption of the liquid by the developing bud. . 



Water was in all cases more favourable to growth than was the 

 nutrient solution ; and distilled water was more favourable than tap 

 water. 



XI. — Summary of Result.s and Conclusions. 



Wilted leaves, whether detached from the plant or not, will absorb 

 water, if immersed, or if water be applied to the surface in the form of a 

 spra\^ Weighing a leaf or a branch to estimate the amount of water 

 absorbed, will be deceptive, because a certain amount of substance is 

 extracted by the water ; and unless this substance be taken into 

 consideration in the weighing, a loss instead of a gain juaj result, and 

 yet an absorption of a considerable amount may have taken place. 



Special parts of leaves of certain plants seem to be adapted to the 

 purpose of absorption as shown by the surface of the epidermal cells 

 over the veins, at the base of the trichomes, and in other regions. 

 Trichomes in some cases are particularly susceptible to the action of 

 water and of solutions applied to them. Striations and hairs or 

 trichomes aid exceedingly in spreading liquids over the regions which 

 seem to be adapted to absorption ; and trichomes prevent a rapid 

 evaporation of the liquid so spread, by retaining air. Absorption of 

 water may take place also through the surface of the petiole. 



Guttation drops and dew-drops contain substances in solution which 



