1910] STOCKBERGER—TOXIC SOLUTIONS AND MITOSIS 411 
the copper solutions. After 7 hours in distilled water there was little 
division in the periblem, the figure in a few cells being in early pro- 
phase. Division was active in the plerome. After 22 hours division 
had ceased in the outer layers, but still occurred normally in the inner 
tissues. In 46 hours the radicles were curved, numerous cells were 
dead, large vacuoles occurred in the cytoplasm, and in many cells 
the achromatic figure was degenerating (fig. 2b). The general con- 
dition after 96 hours is illustrated in fig. 2a. Particularly striking 
are the large nuclei, the cytoplasmic vacuoles, and the interrupted 
cell plate seen in one of the upper cells of the figure. Fig. 2c repre- 
sents a group of cells from a radicle of Lupinus albus after 46 hours’ 
exposure .to distilled water, and is inserted here for the purpose of 
comparison. In these cells also vacuoles occurred in the cytoplasm, 
and there was some degeneration of cytoplasmic structure. 
It appears that the distilled water exerted practically the same 
effect on mitosis as was produced by the dilute copper sulfate solu- 
tions, but only after a more prolonged exposure. 
THE EFFECT OF MORE CONCENTRATED SOLUTIONS OF COPPER 
SULFATE 
In planning the experiments with stronger solutions of copper 
sulfate, some paragraphs from Nemec’s “Ueber ungeschlechtliche 
Kernverschmelzungen” (21) were held in mind. In this paper 
NEMEC describes the production of binucleate cells and other abnor- 
malities by placing the radicles of Vicia Faba for thirty minutes in 
I per cent solution of copper sulfate and then transferring them to 
Moist sawdust for seven hours. NEMEC’s experiment seemed to 
indicate that Vicia Faba was remarkably resistant to the action of 
copper solutions, indeed to a far greater degree than in Lupinus albus, 
in which, as was learned through access to some unpublished notes 
of Dr. R. H. True, some growth can occur after an exposure of eight 
minutes’ duration to a 2/16 solution of copper sulfate. A test quickly 
showed that thirty minutes’ exposure to a 1 per cent copper sulfate 
solution (approximately /12) was fatal to the material being used 
in these experiments. A series of preliminary experiments was 
carried out, therefore, to establish approximately the time limit 
