igoo-i.] Effects of Water on Foliage Leaves. 245 



scant attention is given the subject, and it is plain that Pfeffer had 

 little, if any, experimental knowledge concerning it, though he cites 

 some of the more important works relating thereto. In the work of 

 Detmer (1883, p. 112) is discussed to some extent the question, with the 

 conclusion, that if the tissue of the leaves is fully turgescent, then there 

 will be no absorption, but if not turgescent, then they are capable of 

 taking in water which may be in contact with the leaf surface. Sorauer 

 (1895, p. 32) states that it is only in cases of extreme dryness that 

 plants are able to make use of the heavy deposits of dew. The view 

 expressed by Haberlandt (1896) is worthy of special notice because he 

 goes into the matter more fully, and because his views stand out some- 

 what prominently in contrast to those expressed in almost all the other 

 nrodern text books. He has no doubt whatever that foliage leaves can, 

 and do, absorb water to the advantage of the plant, and he mentions 

 some plants whose leaves function regularly as water-absorbers. In the 

 work of Detmer and Moor (1898) we have the view rather cautiously 

 expressed : — "The question of water-absorption by leaves is not of great 

 physiological interest," — and but a very few lines are devoted to the 

 subject. In Macdougall's work (1898) it is stated that leaves do not 

 absorb water. Very little is said concerning the question in Strasburger 

 (1900), excepting that in some peculiar cases, as in that of scaly hairs, 

 water may be absorbed. In a recent text book on Plant Physiology, 

 that of BelzAuig (1900) the question is discussed with the conclusion 

 that water is absorbed as dew, and may be absorbed under other 

 peculiar circumstances. 



From this brief summary it may be seen that the subject has had a 

 rather peculiar history, and one which is not without interest from the 

 standpoint of physiology as well as that of economic botany. 



The question of the absorption by leaves of solutions introduces 

 a new element into the discussion ; and until quite recently very few 

 experiments of importance relating to the subject have been performed. 

 Whatever work has been done has been from the side of the injurious 

 effects of solutions causing poisoning of the leaves, and even of the 

 whole plant. Boitard (1829) noted that if mist contained saline matter 

 it was injurious to plants ; but no work relating to the question, so far 

 as can be learned, was done until 1872, when R. Angus Smith (1872) 

 was appointed to look into the effect produced upon vegetation in the 

 neighbourhood of chemical works in England. That the fumes from 

 these chemical works did affect the plants injuriously was readily seen, 

 but whether it acted directly upon the leaves or upon the roots was 



