366 BOTANY. 
be distinguished from a similar plant kept in diffused daylight. 2 
This experiment shows that the middle red rays above can support 
the growth of a plant, whilst the outer red rays are unable; and 
also that assimilation is dependent on the quality of the rays and 
not on the intensity of the light. 
W. Pfeffer (in Pogg. Ann. cxlviii, 86-99) interprets Lommel’s 
experiments as only diowiw that more growth takes place under 
the influence of the middle red rays, than under that of the outer 
red rays. 
An abstract of Prof. Draper’s interesting experiments in the 
same field will be given in our next number 
Pe re oe Pe are” ee ee ee ee 
Microscopic PHOTOGRAPHY OF VEGETABLE TissuEs.—Mr. Pedler 
makes the following synopsis of this sketch, by L. Erkmann. 
(Zeitsch. Anal. Chem. xi, 395.) The section of the plant or other 
tissue is to be placed, for a night, in a solution of aniline red, not 
too concentrated. On washing the tissues with water the non- 
nitrogenous tissues are left uncolored, whilst the nitrogenous tis- 
sues remain colored, there being also a considerable amount of 
shading. From a negative thus-prepared, a positive may 
obtained in which the nitrogenous substances are dark and Ke 
non-nitrogenous light. _ 
MPSS. =, etree a ra Li 
EFFECT OF COAL-GAS upon Trees AND Suruss.—A series of 
experiments was tried in Berlin in order to determine the amount 
of damage done to the roots of trees and shrubs by gas escaping 
from pipes through the soil, and thus coming in contact with them. 
It was found that even so small a quantity as twenty-five cubic 
feet per diem, distributed in one hundred and forty-four square 
feet of ground, and at the depth of four feet (that is, through five 
hundred and seventy-six cubic feet of earth), killed in a short 
time the rootlets of trees of every kind which came in contact with 
it, and that this damage was sooner done, the firmer and closer the 
surface of the groppa above. (Ding. polyt. Journ. cevi, 345, 
abstr. by W. Smith : 
PLANTS NEW TO GRAYS Maxvat.— Three years ago, Miss 
Furbish of Brunswick collected at Boothbay, Maine, specimens 
of Odontites rubra. This isa pretty Euphrasioid plant easily 
distinguished from the White Mountain Euphratia — 
Last summer the same plant was collected by Prof. Rockwood, at 
Dee ee oe ee y 
