1900-1.] Effects of Water on Foliage Leaves. 251 



Branches of the following plants were tested : — Rosa, Polygonum, 

 Clematis, Potentilla, Zizia, Acer, Dicentra, Hydrophyllum, Quercus and 

 Tilia ; and as the results were practically the same as those given 

 concerning single leaves, it was deemed unnecessary to give a record of 

 the special observations. In all cases care was taken to have the cut 

 end of the shoot not immersed in the water. It is clear that, had the 

 cut end of the shoot touched the surface of the water, or dipped below 

 it, the value of the experiment would have been destroyed. 



The water in which these leaves were immersed was found to have 

 acquired some substances from the tissue of the leaves, as shown by the 

 litmus indicator. Since leaves lose substance to the surrounding water, 

 weighing of the leaf alone will not determine increase due to absorption 

 of water. It was partly because of this fact that the weighings were 

 correlated with other phenomena in estimating the grade given in 

 column three. The restoration of turgor in cut shoots was more readily 

 determined because the smaller branches, the petioles, as well as the 

 blades of the leaves, aided in making comparisons. These results as 

 tabulated are corroborated by Cailletet, Boussingault and Henslow, who 

 used slightly different methods. 



Duchartre opposed these views by saying that leaves and cut shoots 

 do not function as living plants, and that they may be compared to the 

 detached limb of an animal. It is not difficult to see, that for purposes 

 of comparison, there is little similarity. His chief experiments were 

 performed with -plants in flower-pots, and in consequence he had to use 

 a coarse balance for making his weighings. 



He gives these records : — 



Weight of plant in evening- 1730.6 grams. 



Weight next morning (six o'cloclt) 1733-2 " 



Weight after wiping leaves 1730.8 " 



Weight of plant in evening 1677 " 



Weight next morning (six o'clock) 1679.4 " 



Weight next morning (nine o'clock) 1677 " 



One can see that the weighings could not have been very accurate; 

 and the differences given prove little or nothing either way, as they are 

 scarcely beyond the margin of error in using coarse balances as 

 indicated by those figures. When one examines Duchartre's work, he 

 is more and more struck with surprise at the prominence given to it, in 

 face of the work done by such men as Cailletet, Boehm, Henslow and 

 others. It is not so much an examination into the writings of these 

 men, as it is a study of their experiments, that carries conviction. 



