A Method for Inducing Protoplasmic Streaming 111 
plant, and in different plants collected at different times and in 
different localities, but never in any material did “oligodynamic” 
water fail to arouse a number of cells to active streaming. Many 
cells of the leaves of Elodea are stimulated to abnormal streaming, 
both as to rate and type, after eighteen to forty-eight hours in copper 
water, but many cells also succumb. 
One or two of the unusual types of streaming above described 
may occasionally be observed in untreated cells. Consequently, all 
of the above types cannot be regarded as abnormal. Never, however, 
does an untreated cell exhibit anywhere near so great a variety of 
types, and never such an abundance of streaming at such an extra¬ 
ordinarily high rate as do cells treated in solutions of alcohol, saponin, 
strontium, and copper. 
It is surprising that substances physically and chemically so 
different as are methyl alcohol, the colloid saponin, the electrolyte 
strontium chloride and the metal copper (it is not certain in what 
form copper exists when minute quantities of it go into “solution” 
in water—possibly as an oxide) should all stimulate protoplasm to 
such active and such abnormal streaming. It is further of interest 
to point out that calcium, a bivalent cation like strontium, does not 
arouse protoplasm to activity. 
One naturally seeks for some cause of this stimulation to stream¬ 
ing and especially of the remarkable fact that such diverse substances 
bring about the same end result. Three possible partial explanations 
come to mind—a reduction in viscosity, a decrease in surface tension, 
and an alteration in electrical charge. 
A reduction in viscosity would lessen the resistance against which 
the force causing streaming must act and thus permit a more rapid 
flow. But a reduction in viscosity would not arouse a quiescent cell 
to activity nor produce abnormal types of streaming. Furthermore, 
reduction in viscosity does not apparently always take place, indeed, 
an increase in protoplasmic consistency is sometimes evident. 
Changes in surface tension and electrical charge have been much 
used of late to explain many vital phenomena. That both play an 
important part in living processes is probably true (although one 
worker would have us believe that the living substance is “ electrically 
bland”), but many of the assumptions which have been made rela¬ 
tive to the biological significance of these forces are highly specu¬ 
lative. 
Alcohol, saponin, strontium, and copper all clearly and markedly 
reduce the surface tension of protoplasm, i.e. the tension existing 
