INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 913 



biites this plienomenon rather to the shade cast by trees, and especially 

 to the exhaustion and desiccation of the soil by their roots, which often 

 extend to a great distance. On the other hand there are many plants 

 which seek the neighbourhood of trees, and which even thrive only 

 under their shadow ; and these, probably, must be adapted to a 

 diminution of atmospheric electricity. M. Naudin states that, in 

 some cases at least, the same sjiecies is not only more vigorous, but 

 flowers earlier, with larger flowers, under the shade of trees than in 

 more open situations. 



His general conclusion is that the influence of atmospheric elec- 

 tricity on plants is complex, varying with the species, and being also 

 modified by climate, season, temperature, degree of light and moisture, 

 and perhaps also by the geological structure or mineralogical compo- 

 sition of the soil. 



Absorption of Rain and Dew by the Green Parts of Plants.*— 

 The ancient view of Hales and Bonnet that plants have the power of 

 absorbing rain and dew, was combated by De Candollo, Meyen, Trevi- 

 ranus, and especially by Duchartre, whose conclusions to the contrary 

 elfect have been accepted since his time by nearly all vegetable physio- 

 logists. The subject has been recently reinvestigated by the Eev. 

 G. Henslow, whose experiments appear to have established conclu- 

 sively that the older view is the correct one. Not only has this 

 conclusion been confirmed by an independent series of researches 

 carried on by M. Bousingault,| but it is in harmony with the practical 

 experience of all horticulturists. 



Without entering into the details of his experiments, which will 

 be found recorded in the paper itself, it may be stated in general 

 terms that the results arrived at by Mr. Henslow are, that dew is not 

 absorbed by saturated tissues at night ; but that absorption does take 

 place at and after sunrise, when transpiration recommences, and an 

 indraught is caused by the moisture retained on the leaves ; further, 

 that when leaves are purposely or naturally killed by excessive drought, 

 they then do absorb water ; as may be proved by the balance, and in 

 other ways. 



Decrease of the Power of Absorption in Branches dipped in 

 Water 4 — From a fresh series of investigations on this subject, Dr. F. 

 von Hohnel has come to the conclusion that experiments on the rate 

 of absorption of fluid by cut branches have little value in determining 

 the phenomena which take place in the living plant, an important 

 factor in the former being that the decrease of absorption which takes 

 place after a time is largely due to the formation of mucilage and the 

 appearance of bacteria, causing a partial or entire closing of the 

 vessels. 



'Water-pores.§ — Under this term Langer describes those orifices in 

 the epidermis of the leaves and other green parts of plants which serve 



* ' Journ. Linn, Soc. (Bot.),' xvii. (1879) p. 313. 

 t ' Ann. Chim. et Phys.,' May 1878. 

 X ' Bot. Zeit.,' xxsvii. (1879) pp. 297, 313. 

 § ' Oesterr. Bot. Zeitsclir.,' xxix. (1879) pp. 79, 105. 

 VOL. II. 3 P 



