1913] CURRENT LITERATURE 85 
In the third paper,” dealing with chromosome reduction, the material 
used was Smilacina, Kniphofia, and Aloe. LAWSON finds no continuous 
spirem at any stage, but always a number of separate threads, probably as 
many as there are chromosomes. Even in the reticulum the threads are double 
and the double character becomes more pronounced in later prophase. If 
these two parts of each chromosome should separate at this stage, an ordinary 
vegetative division with the diploid number of chromosomes would result; 
but, as the threads shorten and thicken, the double character becomes indis- 
tinguishable, so that each thread appears single. These apparently single 
threads now unite laterally in pairs, forming bivalent chromosomes, and the 
two members of the bivalent chromosome are separated at the heterotypic 
mitosis, so that entire vegetative chromosomes pass to the pole, thus accom- 
plishing the reduction in number. Although the conclusions are contrary to 
generally accepted views, the figures and arguments seem convincing.— 
CHARLES J. CHAMBERLAIN. 
Changed permeability and antagonism.—During the last half-decade 
LEPESCHKIN, TRONDLE, and other workers have developed accurate methods 
for determining the rate at which various solutes (NaCl, KNO,, glycerine, 
glucose, etc.) enter the plant cell. LEPESCHKIN states the degree of permea- 
bility in the following unit: molecular weight entering unit surface of the cell 
cell. These methods have been applied in determining the effect of various 
conditions and reagents upon the permeability of the protoplasm to the solutes 
studied. The work as a whole establishes that marked changes in permeability 
to nutrient salts and other solutes are produced by variations in temperature 
or light-~intensities and by the application of anesthetics or certain salts. It 
also involves definite measurement of the magnitude of the permeability 
changes and leads to the generalization that in nature the protoplasm of plant 
cells changes in its degree of permeability from hour to hour with the changing 
condition, and that there exist daily, seasonal, and annual rhythms of permea- 
bility changes. It is rather hard to over-emphasize the physiological signifi- 
cance of these facts in explaining phases of plant activities. For example, 
LEPEscuKIN has found that variation movements in plants are caused in the 
main by modified permeability of pulvinal cells to contained solutes, which 
is induced by changing environment or internal conditions. 
Now Sziics"® believes he has shown that the antagonistic action of various 
metallic ions toward other metallic ions, alkaloids, and basic dyes is due to the 
antagonistic ions reducing the rate at which the toxic agents mentioned enter 

7 Lawson, A. A., A study in chromosome reduction. Trans. Roy. Soc. Edinburgh 
48:601-627. pls. 1-3. 1g12. 
** Sztics, Josera, Experimentelle Beitrige zu einer Theorie der antagonistischen 
Tonenwirkungen. Jahrb. Wiss. Bot. 52385-1242. 1912. 
