124 BOTANICAL GAZETTE [ FEBRUARY 
heliotropic and geotropic stimuli. (5) Reaction to electrical 
stimulation is limited to a narrow range in current intensity, 
The reaction is manifested either in an acceleration or retarda- 
tion of metabolic activity, according to the nature or the! 
strength of the current employed. (6) There is a minimum, 
optimum, cessation, and maximum stimulus. (7) The excita 
tion produced by alternating currents is more marked than that 
produced by direct currents. (8) The increase of stimulis 
necessary to produce an equally noticeable. difference of per: 
ception bears a constant ratio to the total stimulus intensity; 
the relationship existing between the perception and stimulusi 
expressed by the ratio 1: 3 (Weber’s law). . 
Some notes upon the germination of spores: C. O. TOWNSEND, 
Maryland Experiment Station Experiments were undertaker 
distilled water under different conditions of temperature allt 
light. Spores of Mucor, Penicillium, and other fungi were placed 
in test-tubes partly filled with distilled water. Some tubes wet 
subjected to the out-door changes in temperature; others wet 
kept at a nearly constant temperature of 18° in diffused light; 
others at the same temperature in the dark; and still others # 
25° in the light. The spores were tested from time to time 
removing a few from each set of tubes and placing them upons 
mixture of gelatine and sugar in moist chambers. So ees 
the spores that were exposed to the natural fluctuations © 
temperature did not freeze they retained their ability to ge 
nate in the usual time (12-16 hours). After freezing, hon 
they did not germinate. The other spores retained for at | C 
six months their ability to germinate in the usual time. ~~ 
growth of the mycelia and the ability to form new Spor eS 
not affected. © : 
Sensitiveness of certain parasites to the acid juices of the host pla: 
Erwin F, Smiru, Department of Agriculture.— The ie 
tively slow progress of Pseudomonas campestris, P. phaseolt, 
Ayacinthi when inoculated into the host plants, even in ene ie : 
