1904 | CURRENT LITERATURE 229 
abbreviated. The author concludes by stating that we have here an embryo 
which cannot develop without fungal symbiosis, just as an egg commonly has 
to be fertilized before it can develop.— H. C. CowLEs 
A PAPER BY HELLER ™ on the influence of ethereal oils and the like upon 
plants comes from the Leipzig laboratory. Plants were subjected to the 
influence of such substances as the oils of Eucalyptus, Citrus, Salvia, Thymus, 
Origanum, Mentha, Pinus, etc., and of gum camphor, thymol, etc., as well as 
of petroleum ether, petroleum, benzine, benzene, xylene, anilin, phenol, etc. 
These substances are more poisonous in vapor form than as liquids or in aque- 
ous solution. Plants which produce an oil are somewhat immune to its action. 
Volatile hydrocarbons act like ethereal oils. As would be expected, all these 
e Substances enter the cell by going into solution in the water of imbibition of 
the cell walls and then diffusing as solutes. But, as would not be expected, 
a dry membrane appears to be a poorer protection to the plant than a moist 
one. Resin and paraffin failed to gain an entrance into the cells.—B. E. 
LIVINGSTON. 
Dixon has replied to criticisms of the cohesion theory of the ascent of. 
water” by Steinbrinck and by Copeland. To Steinbrinck’s contention that the 
permeability of lignified walls to air renders the Dixon-Joly theory untenable, 
he replies briefly that the gas is chiefly in solution, in which state, as h 
already been shown, it does not interfere with the transmission of tensions in 
water columns. Furthermore, even if the gas is free it only interrupts ie 
function of the vessel in which it develops. Chief attention is tlie 
Copeland, ® whose methods and interpretations are criticized. goes 
that the manometers as arranged in Copeland’s apparatus betes aa local 
differences of gas pressure and of water pressure, the latter produce ed 
long continued absorption of water after the plaster has set. This peculiarity 
of plaster may be a source of error in Copeland’s work; the other criticisms 
do not appear valid to one familiar with his experimentation.—C. R. B. 
THE POLLEN TUBE structures of Cupressus Goveniana, as recently 
described by Juel,’? are extremely interesting. Up to the division of the 
body cell, the sequence is as in other members of the Cupresseae, there being 
a stalk nucleus, a tube nucleus, and a body cell. The body cell, however, 
instead of giving rise to two sperm cells, gives rise to a cell complex gon- 
sisting of a variable number of cells, sometimes four, oftener eight or ten, 
» 
a. 
"HELLER, A. Ueber die Wirkung dtherischer Ole und einiger verwandter Korper 
auf die Pflanzen. Flora 93: I-31. 
7 Dixon, H. H., The cohesion theory of the ascent of sap. Sci. Proc. Roy. 
Dublin Soc. ro!: 48-61. 1903. 
**CoPELAND, E. B., The rise of the transpiration stream: A historical and 
critical discussion. Bort. Gaz. 34 :161-193, 260-283. 1902. 
9 JUEL, H. O., Ueber den Pollenschlauch von Cupressus. Flora 93: 56-62. pi. 3. 
1904. 
