912 RECORD OF CURRENT RESEARCHES RELATING TO 



Relationship of Intercellular Spaces to Vessels.* — Dr. Von 

 Hohnel points out that one important functional diiference between 

 true vessels and intercellular cavities is that, while in the latter the 

 pressure of the air never differs materially from that of the sur- 

 rounding atmosphere, in the former it may either be considerably less 

 (when transpiration is very active), or in some cases more than double 

 as great. Except in a few special instances, the fibrovascular bundles 

 consist of vessels in close apposition with one another, without inter- 

 cellular spaces. 



In these exceptional cases the author has succeeded in establishing 

 the following laws : — (1) In no case, in the vascular bundles of the 

 stems of Phanerogams, is a vessel which is still functional bounded 

 immediately by an intercellular space. (2) In the leaves of Phanero- 

 gams a tracheid or vessel is never directly bounded by an intercellular 

 space. (3) Throughout the plant the functional vessels and tracheids 

 are always separated from the intercellular spaces by at least a single 

 layer of living cells. 



Peculiarities in tlie Power of Living Parts of Plants to conduct 

 Electricity- 1 — Investigations of this subject conducted in Sachs's 

 botanical laboratory in Wiirzburg, have led Dr. Kiinkel to conclusions 

 which may be briefly summed up as follows : — Parts of plants, the 

 elongation of which is mainly in one direction, exhibit differences in 

 the power of conducting electricity according as the direction of 

 growth is ascending or descending. 



Influence of Electricity on Vegetation-I — A series of experiments 

 carried on by M. Naudin appears to lead to an almost opposite con- 

 clusion from the results previously transmitted to the Paris Academy by 

 MM. Grandcau and Leclerc, that the flowering and fructification of 

 plants are retarded and impoverished when they are excluded from the 

 influence of atmospheric electricity. 



The earlier experiments were made on tobacco and maize at 

 Nancy and Mettray ; and later ones on the tomato and other plants in 

 the warmer climate of Antibes. In both sets isolation was effected by 

 enclosing the plants in an iron cage, covered with a small-meshed iron 

 netting. For the first fortnight of M. Naudin's experiments, there 

 was no apparent difference between the plants in the cage and others 

 grown under precisely similar conditions outside it ; but after this 

 time the plants in the cage were decidedly stronger than those in the 

 open air, and this difference became more pronounced as time went on. 

 The periods of flowering, and of the formation and maturing of the 

 fruit, were contemporaneous ; but as regards the quantity of vegetable 

 matter produced in a given time and on the same extent of soil, there 

 was a great difference in favour of the caged plants. M. Grandeau 

 believed that trees exert an injurious influence on plants in their 

 neighbourhood by withdrawing atmospheric electricity from them ; 

 but this again was not confirmed by M. Naudin's results. He attri- 



* 'Ocsterr. Bot. Zeitschr.,' xxix. (1879) p. 137. 

 t ' Alb. Bot. lust. Wurzburg,' ii. (1879) p. 338. 

 j ' Coniptos Reiuhis,' Ixxxix. (1879) p. 535. 



