Noteworthy anatomical and physiological researches. 
Physiological action at a distance. 
Dr. Elfving has published an additional paper? concerning 
the effect of different bodies upon the sporangiophores of Phy- 
-comyces nitens. Erxrera (see Bot. Gaz. 18: 196. 1893) 
explained the attractive or repulsive effect of different met- 
als, etc., upon the organs named as manifestations of hydrto- 
tropism inthe latter. Elfving now publishes new experiments. 
If iron acts as a hygroscopic body upon the negatively hy- 
drotropic sporangiophores, we may expect to see the phenom- 
enon most plainly when the fungus is exposed to the influence 
of such highly hygroscopic bodies as calcium chloride. The 
result was, however, negative. ‘ 
A very hygroscopic plate of gypsum (80x 35 X 10™"), dried | 
at 100° C., and placed among the sporangiophores 1 pees 
atmosphere saturated with water, had no effect whatever upon 
these. [To those who have done experimental work with 
here was no hygro 
s, Erreta 
rdsa place 
oisture, 
streaming of the molecules in the air is the ! 
tropic irritability. The first statement is con 
experiments of Du Hamel, Knight, Johnson, 
chartre, Sachs, Pfeffer, and Molisch.] This gypsum 
condensed 1.665% of water. An iron plate (surface of ek : 
‘**™™) had a well marked attractive effect, and condensed om 
3.5°"" Of ‘water: pe 
Elfving comes to the conclusion that these anise ‘oe 
caused by molecular movements. Highly polishe a 
platinum have very little effect upon the sporangiophot ae 
t for a long 
if these metals are exposed to direct sunligh ‘ 
they become active, i. e., they are brought into such a ‘ ale 
tion that they attract said organs. This active conditio 
lasts for some hours, and then it disappears. — 
1 Zur Kenntniss d. pflanzlichen Irritabilitat.—Sep. from 
Vetensk. Soc. Foerh. Haeft 36. 1893. 
Oetversigt 
