196 The Botanical Gazette. (May, 
n 1890, Prof. Fr. Elfving, of Helsingfors, gave a communi 
on physiological action at a distance, showing a remarkable kind 
borhood, such as metals of different kinds, etc. Iron attracts the 
iin 'sporangium- -bearers very distinctly; less noticeable was the 
effect of zinc and aluminium; gold, silver, nickel, lead, and on ] 
| P 
sia tty, that Poe pi due to hydrotropism, and his facts are the fol 
lowing: China clay, which is very hygroscopic, attracts energeticall 
but china exhibits no attraction; agate, which is very hygroscopls 
strongly attracts the filaments, while rock-crystal does not exhibit aay 
effect, owing to its non-hygroscopic properties. fe. ee 
hygroscopic. —Bay 
THE FOLLOWING See from the annual report of its Pr 
Harvard University-is of interest to botanists: “On th 
resident o : 
cath 
from 
increase ye 
ase of the 
a, at the Her The result has been : na grata the coF 
1S 
1 or physiologische Fernwirkung einger Koerper. Helsingfors 4 
. . 
cen cause of physiological action at a distance. Annals of Botasy” 
8 Jhmori: Weidemann's Annalen, 1887. 
