474 BOTANICAL GAZETTE [DECEMBER 
From A series of experiments in which the radicles of seedlings were employed 
as physiological reagents, DANDENOS° concludes that the theory of electrolytic 
dissociation is without support from the physiological side. The author also 
finds, as TRUE and OGLEVEE have already shown,3! that the toxic effect of cer- 
tain solutions is greatly reduced by the mere presence of non-chemical bodies, 
such as pure sand whose property of physical affinity retards chemical action 
and physiological effect. The economic significance of these facts is also stated. 
Other factors regarded as affecting toxicity of solution are quantity of solution, 
rate of diffusion, Pe of container, and even the glass walls of the container. 
—Raymonpd H. Pon 
Two nores of interest in relation to the way in which the powdery mildew 
and downy mildew live through the winter are published by IstvANFrr.3? As is 
well known the perithecia of the powdery mildew rarely occur in Europe, and 
according to the author they have not been found in Hungary. Patches of 
mycelium, however, are said to remain alive during the winter on the stems and 
dried clusters of grapes left on the vines. From these fresh conidia were pro- 
duced when taken into the laboratory in January. Similar observations, the 
author states were made by Appet. The mycelium of the downy mildew is 
also found33 to survive the winter in parts of the vine, especially in the buds, thus 
confirming the observations of CuLont.—H. HassELBRING. 
To ASCERTAIN the influence of a periodical dry season upon the meristematic 
activity of the cambium, Ursprunc34 has studied the anatomy of certain species 
common to Buitenzorg and East Java. The climate of the former locality is 
uniform, while that of the latter shows a distinct periodicity of wet and dry seasons. 
He finds as a general rule (for representatives of six different families) that material 
from East Java shows a much more complete and distinct zonation of w: 
structure than specimens of the same species from Buitenzorg. Species vary, 
however, in susceptibility to climate, since the one which shows the relatively 
clearest zonation in Buitenzorg may not sustain this relation in a group of the 
same species from East Java. The influence of foliation and defoliation upon 
3° DANDENO, J. B., The relation of mass action and physical affinity to toxicity, 
with incidental pr eRORES as to how far electrolytic dissociation may be involved- 
Amer. Jour. Sci. IV. 17: 437-358. 1904. 
3 Teve:R. H., and OcLeEVEE, C. S., The effect of the presence of insoluble sub- 
stances on the toxic action of poisons. Science N. S. 19:421. 
3? IstvAnrri, Gy. DE, Sur l’hivernage de l’oidium de la vigne. Compt. Rend. 
Acad. Sci. Paris 138: 596-597. 1904. 
33 IstvAnrri, Gy. Dk, Sur la perpétuation du mildiou de la vigne. Compt. Rend. 
Acad. Sci. Paris 138:643-644 1904. 
34 Ursprune, A., Zur Periodicitit des Dickenwachsthums in den Tropen. Bot- 
Zeitung 62": 189-210. 1904. 
