* 
1906] CURRENT LITERATURE 455 
a strong salt solution (16.2%), and then transferred gradually to normal sé 
water. In nearly all cases the protoplasts regained almost entirely their orleicisl 
size, a few remaining in the plasmolyzed form. An active growth promptly 
set in, by which the form of the alga was entirely changed. First the proto- 
plasm of the last-mentioned cells, by means of rounded or tube-like outgrowth, 
finally filled up the original space within the cell walls. Then all the cells grew 
in this way: the basal end of the cell pushed into the cell below in the form of 
tubes, often growing between the protoplasm and the cell wall; or occasionally 
the whole cell bulged into its neighbor. hen one cell is dead, the next above 
grows in and fills it completely. Often from the lower angles of the cells tubes 
grow downward into the cells below. Many of these tubes assume the char- 
acter of rhizoids. All of these outgrowths occurred at the basal end of the cell, 
not a single one from the apical end. Later, unless the upper cells begin to 
produce branches, they do so rs aes from the apical end. A. very Te 
polarity of the cell is thus se 
Some interesting results on eee and organ- Se ectuein on Caulerpa ‘ie 
lifera have been contributed by JANSE.’® This plant he shows to possess a well- 
marked polarity in the formation of “leaves” and rhizoids, and also in the 
streaming of the protoplasm, which is always from the apex toward the base. 
Following a wound there appears to be a division in the protoplasm, the chlo- 
tophyll-bearing portion separating from a colorless turbid portion. It is the 
latter, according to JANsE, that occasions the formation of new organs. The 
polar phenomena he considers dependent upon a flow of energy in which 
the force acts always in the direction of the base. This stream of energy he 
calls the “‘basipetal impulse.’”? The opposite, an acropetal impulse, was not 
to be detected, and JANSE concludes that ‘the lack of an ‘acropetal impulse, 
implies the lack of a second pole at the organic tip.”? Thus we have a polarity 
with only one pole. The author applies this conception to polarity as seen 
in the higher plants. The point of view is more interesting than convincing. 
OBLER’® uses some observations on Polysiphonia and Ceramium as the 
basis of a lengthy and rather elusive discussion on regeneration and polarity. 
He sees a difference in the lower and higher plants in respect to polarity, which 
he considers rests on the differentiation of tissues, and accompanies the division 
of labor in the plant—W. B. MacCatium. 
Roots of Monocotyledons.—LINDLINGER?° has reopened the question of 
the place of origin of the secondary growth shown by the roots of some mono- 
18 JANSE, M. J., Polaritat und Organbildung bei Cawlerpa prolijera. Jahrb. 
Wiss. Bot. 42: 394-460. pls. g-II. 1906. 
‘9 TOBLER, FR., Ueber Regeneration und Polaritat sowie verwandte Wachstums- 
vorgange bei { Polysiphona und andern Algen. Jahrb. Wiss. Bot. 42: 461-502. pis. 
12-14. 1906 
20 LINDLINGER, L., Zur Anatomie und Biologie der Monocotylenwurzeln. Beih. 
Bot. Cent. 19: 321-358. 1905 
