340 Morphologie, Teratologie, Befruchtung, Cytologie. 



rials available may be considered as representative of the species 

 it is generally negative, i. e., as the number of ovules formed in 

 creases the capacity for maiuring these ovules into seeds decreases. 

 This conclusion is supported by the facts that the negative correla- 

 tions are significantly more numerous than the positive, they average 

 larger numerically, and the}»^ have a higher degree of trustworthi- 

 ness with regard to their probable errors. 



In some varieties, however. the correlations seem to be gene- 

 rally positive. This is true for the common Navy. All other varie- 

 ties so far as studied show exclusively or preponderantly negative 

 correlations. 



Concerning the explanation of this relationship no Suggestion 

 can be made. Such an attempt would be quite premature until 

 ample quantitative data on the nature (sign) and intensity of the 

 relationship in a considerable series of varieties are available. 

 Anyone venturing to suggest explanations must also fully realize 

 that the problem is an exceedingly complex one, involving many 

 difificulties. But as matters of biological fact the results seem defini- 

 tely established, and represent one further step in the analysis of 

 the problem of fertility and fecundity in plants. Jongmans. 



Lillie, R. C, The röle of membranes in cell processes. 

 (Pop. Sei. Month. LXXXII. p. 132-152. 1913.) 



The surface films of living cells consisting of both lipoids and 

 proteins exhibit two physical characteristics which are especially 

 observable: 1) semi-permeability during lite, and 2) the capacity to 

 undergo reversible changes in permeability toward dissolved sub- 

 stances. The antagonism existing between the ph5^siological action 

 of various substances is probabl}^ in many cases to be explained on 

 the basis of a change in permeability of the membranes. It has 

 also been found, as far as investigated, that the process of Sti- 

 mulation is always accompanied b}'" an increase in permeability, and 

 probably is often dependent on it. Stimulation of a tissue by the 

 electric current appears to be a function of the changing permea- 

 bility of the plasma membrane. Conversely, when tissues are treated 

 with substances which increase the permeability of the plasma 

 membrane, a difference in potential results, due to a difference in 

 the rate of diffusion of the electric ions in the cells. This is brought 

 about by a change in the polarization of the semipermeable mem- 

 brane, and this change alters the permeability so that there is a 

 difference in the rate of diffusion of the electric ions. 



L. 0. Overholts (Sl. Louis). 



Mottier, D. M. and M. Nothnagel. The development and 

 behavior of the chromosomes in the first or heteroty- 

 pic mitosis ofthe pollen mother-cells oi Alliian cernunrn 

 Roth. (Bull. Torrey Bot. Club. XL. p. 555-565. PI. 23, 24. 1913.) 



At the end of their paper the writers publish followingsummary: 

 The resting nucleus prior to synapsis consists of a reticulum 



of linin and chromatin granules and of one or more nucleoli. The 



"Chromatinknoten" of Bonnevie are not present. 



Before sinapsis there is, as in Lilium, a tendenc}^ to form a 



delicate continuous thread or spirem. There is no union of two spi- 



rems in synapsis. 



