496 
Seifriz.—Observations on the Reaction of 
has risen 1*5 per cent, above the control (to 4*5 per cent. KNOn), in four 
days to 2-5 per cent, above normal, and in five days the cells cannot be 
plasmolysed with a 10 per cent. KN 0 3 solution. They are, therefore, in all 
probability dead (a very few cells remain alive). 
While the reduction (and subsequent increase) in the osmotic pressure 
of alcohol-treated cells is quite clearly seen when the values of critical 
concentrations of salts are used to plot a curve, as in Fig. 4, the most 
convincing demonstration of the reduction in osmotic pressure of a cell 
resulting from treatment in alcohol is to be had by observing the immediate 
effect of a plasmolysing salt of a concentration slightly above the critical 
for untreated cells. 
If Etodea leaves of average resistance to alcohol are left in 8 per cent. 
(1*4 M) ethyl alcohol for six or eight hours and are then plasmolysed, 
together with untreated leaves, by a 4 per cent. KNO s solution, practically 
every protoplast in the treated leaves will be prominently plasmolysed into a 
sphere within two minutes , while of the control leaves only relatively few 
cells will be but slightly plasmolysed. 
Another of the physiological changes which an alcohol-treated cell 
undergoes is a pronounced stimulation of protoplasmic streaming. 
Stimulation of Protoplasmic Streaming. Short treatment in 10 per 
cent, ethyl alcohol is too brief a time in which to arouse the cells to active 
streaming before death ensues, but in low grades of alcohol with longer 
treatment the increase in streaming—in rate, in number of cells exhibiting 
it, and in types of streaming—is very marked indeed. For example, in 3, 
4, or 5 per cent, alcohol after two or three days of treatment nearly half of 
the total number of cells in a leaf exhibit active streaming. 
While the amount and rate of streaming is very pronounced in alcohol- 
treated cells, the most interesting feature of this stimulation to protoplasmic 
activity is the great variety of abnormal types of streaming. In an alcohol- 
treated cell, the chloroplasts may be arranged in a belt encircling the 
protoplast at its centre. There may at times be two such belts, one at each 
end of the cell. Especially interesting is the fact that these two belts of 
chloroplasts in a single cell may be revolving in opposite directions. There 
may also be active streaming of a few chloroplasts around a mass of 
quiescent chloroplasts, the latter so fixed in their position that they are 
not dislodged and drawn into the stream even when the streaming chloro¬ 
plasts rub against them. 
Conclusion. 
The initial effect of ethyl alcohol on the Elodea leaf cell is a pro¬ 
nounced increase in protoplasmic permeability permitting an exosmosis 
of electrolytes which results in a lower osmotic pressure within the cell, 
and, consequently, in a lower critical plasmolytic concentration. These 
