498 
Seifriz.—Observations oti the Reaction of 
PART II. 
THE REACTION OF PROTOPLASM TO THE GLUCOSIDES, 
SAPONIN, SMILACIN, AND SENEGIN. 
Experimental Data. 
Lethal Effect of the Glucosides. What has been said of alcohol could 
almost be repeated to describe the effect of saponin on protoplasm. The 
rate at which the cells are killed, the rapid decrease in osmotic value of 
the cell contents as a consequent of increased permeability, and the 
marked stimulation to streaming, are all equally pronounced in cells 
treated in saponin as in those treated in alcohol. 
If leaves of Elodea are placed in a one per cent, solution of sapo¬ 
nin, smilacin, or senegin, very few of the cells will be killed in two days by 
saponin, half will succumb from the effects of smilacin, and more than 
three-fourths will be killed by senegin. These values are averages. 
Some cells will resist the toxic effect of a one per cent, solution of sa¬ 
ponin for six days (of a half per cent, solution for ten days), and of a 
one per cent, smilacin solution for three days. Senegin is much more 
toxic. A one per cent, solution of this glucoside will, in twenty-four hours, 
cause harmful effects which are observable to the unaided eye in the dis¬ 
coloration of the leaves. 
Changes in Permeability. If the critical concentrations of a plasmo- 
lysing salt are periodically determined for cells which have remained in 
a one per cent, solution of saponin for from one-half to six days, the 
values will gradually fall below the normal for two or three days, the time 
depending on the resistance of the cells to saponin, and then rise to the 
normal and beyond it. The average reduction in critical concentration of 
salt is o*5 to o>75 per cent. The greatest reduction obtained was one per 
cent, after sixty-six hours of treatment (control 3-5 per cent, of KN 0 3 , 
treated 2-5 per cent.). After seventy-two hours’ treatment the critical 
plasmolytic concentration of treated cells may be double that of the normal, 
namely 6 per cent. It is evident, therefore, that the curve in Fig. 4, based 
on data obtained from alcohol-treated cells, would, with slight modifica¬ 
tion, serve to demonstrate the change in critical plasmolytic concentration 
(and therefore of osmotic pressure) of saponin-treated cells. 
As stated in the case of alcohol-treated cells, the most convincing 
demonstration of the reduction in critical plasmolytic concentration and 
osmotic value of the treated protoplast is to be had by observing the 
immediate effect on untreated and treated leaves of a plasmolysing salt 
of a concentration slightly above the critical value for normal cells. If 
this is done in the control leaf some fezv cells zvill be slightly plasmolyscd 
