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A METHOD FOR INDUCING PROTOPLASMIC 
STREAMING 1 
By WILLIAM SEIFRIZ 
T he teacher of biology is often confronted with the task of finding 
material with which to demonstrate protoplasmic streaming. The 
material usually employed for this purpose is Elodea. Frequently, 
however, one may search for hours without success, or, if streaming 
cells are located beforehand, they are likely as not quiescent at the 
very moment that they are needed for demonstration. It should, 
therefore, prove of advantage to know some means by which stream¬ 
ing can be induced, so that one can be certain of having the desired 
material ready when it is needed. 
While studying the reaction of protoplasm to various reagents, I 
observed an extraordinary amount of streaming, often at a very high 
rate, in the cells of Elodea which had been treated in certain of these 
reagents. Once having ascertained the comparative resistance of the 
cells to a reagent, it was an easy matter to obtain an abundance of 
streaming by treating the cells for a definite length of time. 
In addition to a great amount of active streaming, the type of 
streaming was frequently abnormal. Indeed, no less than half a 
dozen distinct types of streaming were observed, and these were 
often in the majority as compared with the normal rotational type 
usually seen in the cells of an Elodea leaf. 
Methyl alcohol was the chemical in which a pronounced stimula¬ 
tion of protoplasmic streaming was first observed. 
The length of treatment in solutions of alcohol varies not only 
with the per cent, of solution used but also with the resistance of the 
cells to alcohol. Those cells situated in the centre of a leaf are least 
resistant. The two or three hundred cells situated in the very base of 
the leaf are most resistant. Not only do the cells in one leaf vary 
greatly in their sensitivity to alcohol, but different leaves on the 
same shoot and different shoots collected at different times and in 
different localities show a greater or less resistance to the toxic effect 
of alcohol. 
1 The research work from which the data here presented were obtained 
was done at the Botanical Institute of the University of Geneva where the 
writer enjoyed the privileges of a guest through the courtesy of Professor 
R. Chodat. 
