1904] CURRENT LITERATURE 477 
ascogonium. ‘The account of M. Barkeri follows the same general outline with 
some differences as to details. The protoplasm of the ascogonium is divided 
into sections by irregular vacuoles. These sections become free cells within 
which the spores are formed. In the summary one spore is said to be formed 
from each of the eight nuclei in the free cell; in the text, however, the spores are 
described as possessing many nuclei. The paper contains also a long discussion 
of the Hemiasci and the phylogeny of the ascomycetes.—H. HASSELBRING. 
NATHANSOHN?? continues his investigations of the nature and functions of the 
plasmatic membrane in plants. The following points are now announced. 
slices of Dahlia tubers be placed in 2 per cent. Na,S,O, solution for two days, 
they absorb the salt to such an extent that at the end of the experiment its concen- 
tration within the tissues is about one-sixth of that without. If now these slices 
be changed to a solution of the same salt of a concentration equal to that now 
within the tissue, there occurs a marked outward diffusion, so that at the end of 
another two days the inner concentration is considerably less than one-half of the 
outer one. This means, of course, that the salt has passed through the plasmatic 
membrane in a direction from the weaker to the stronger solution, 7. e., against 
its own diffusion tension. This case substantiates similar results already pub- 
lished by the same author. 
Furthermore, slices of the tubers of Helianthus tuberosus and of the roots of 
the red beet placed in solutions of NH,Cl, NH,NO;, (NH,)2S20;3, (NH,)250,, 
and (NH,),HPO,, absorb much more of the ammonium ion than of the anion. 
This is not accompanied by an increasingly acid reaction of the external solution. 
The last observation led to an investigation of the substances which might diffuse 
out from the cells, and enough Mg was found to have escaped to account for 
about three-fourths of the NH, which had entered. The author supposes that 
some other cations, perhaps in part organic bases, must be given out from the 
cells, and thus explains the lack of acidity. It is possible also to cause the extru- 
sion of Mg by subjecting these tissues to a solution of a potassium salt. K is 
absorbed and Mg replaces it in the external solution. 
A very interesting theoretical discussion makes up a good part of the paper, 
in which the nature of the protoplasmic layers is considered in the light of the 
new facts, but this cannot be entered into here.—B. E. LrvincstTon. 
Briccs and McCatz4" have devised an ingenious method for investigating 
soil solutions and the rate of movement of such solutions in the soil. The appara- 
tus consists, briefly, of a porous porcelain filter tube connected with a vacuum 
chamber. The wall of the tube is saturated with water, and in this condition it 
can be exhausted to the vapor pressure of water, and will maintain this nearly 
(°c ee 
gulation der Stoffaufnahme. 
4° NATHANSOHN, A., Weitere Mitteilungen iiber die R 
Jahrb. Wiss. Bot. 40: 403-442. 1904. 
4t Briccs, L. J. and McCatt, A. G., An artificial root for inducing capillary move- 
ment of soil moisture. Science N. S. 20:566-568. 1904. 
