316 BOTANICAL GAZETTE [OCTOBER 
Turgor in yeast.—PANTANELLI having examined the regulation of turgor 
in certain fungi and distinguished ‘‘cell pressure”’ into two factors, (1) osmotic 
pressure or turgor, due to solutes, and (2) tension, due to imbibition, has investi- 
gated by the same methods the turgor regulation in yeast derived from Roman 
bread.'? He finds that during fermentation turgor at first increases, then remains 
constant, and finally diminishes when the nutritive value of the medium becomes 
much lowered. The power of osmotic regulation depends primarily upon nutri- 
tion. If the foods are temporarily removed without altering the concentration 
of the medium, the turgor and the tension diminish rapidly, the plant being 
compelled to use its own reserves, forming vacuoles. If grown in water or 
allowed to dry slightly, turgor diminishes, but the tension increases, in the first 
condition until death, in the second up to a maximum, after which it diminishes 
greatly before death. With age the power of osmotic regulation is gradually 
lost. Aeration facilitates it so much that it seems admissible to say that the 
Roman yeast lives during and after fermentation only because it falls into a state 
of narcosis more or less profound.—C. R. B. 
Blast of rice.—MetTCcALr’3 has recently published an account of the “ blast” of 
rice with short notes on other rice diseases. This blast is characterized by lesions 
at one or more of the nodes of the stem above which the stem dies. It has often 
been confused with other diseases or injuries and the true extent of its damage 
not realized. The disease is promoted by resting the land or by applying nitro- 
genous fertilizers. It can be produced in healthy plants by inoculations directly 
from diseased plants, but the organism causing the disease has not yet been fully 
determined. The use of lime and marl with potash and phosphorus is recommend- 
ed as fertilizer treatment that tends to reduce the tendency to blast. The disease 
is prevented by spraying with Bordeaux mixture, but this treatment is not prac- 
ticable with this crop. The search for immune plants has been of no avail up to 
this time.—E. Mrap Writcox. 
A new chestnut disease. —-Murriu" has described a new and serious disease 
of the native chestnut, which is epidemic in many parts of New York City and 
threatens to destroy all the chestnut trees of that region. The disease is also 
known to occur in New Jersey, Maryland, District of Columbia, and Virginia. 
“The fungus attacks twigs, branches, and trunks, irrespective of size oF posi- 
tion, and usually proceeds in a circle about the affected portion until it is com- 
_ girdled.” It is described as a new species of Diaporthe (D. parasitica). 
eae A Se 
12 PANTANELLI, E., Richerche sul delle cellule dj ievito. Annalidi Botanica 
4:1-47. 1906. - 
13 — H., A preliminary report on the blast of rice, with notes on other 
rice diseases. Bull. N. ‘Car. Exp. Sta. 12t:1-43. 1 
go6. 
14 seine W. A., A new chestnut disease. Torreya 6: 186-189. 
