On the Physiological Action of some of the Heavy Metals in Mixed 
Solutions * 
BY 
RoDNEY H. TRUE wets WILLIAM J. GIES 
U. S. Department of Agriculture New York Botanical Garden 
It has been shown by several investigators that, in mixed so- 
lutions containing the lighter metals, the physiological action of 
the electro-positive elements may in a degree antagonize each 
other, and a mixture of several toxic solutions of these compounds 
may be much less harmful than any one of the constituents taken 
singly. Researches concerning the physiology of sea-water have 
shown this to be conspicuously the case. Work on soil-solutions 
by Kearney and Cameron + has developed a similar situation. 
The neutralizing action of the various ions on those of the 
heavy metals has been less studied and the present paper presents, 
in a preliminary way, results gained from a series of experiments 
performed during the summer of 1902 in the Plant Physiological 
Laboratory at Wood’s Hole, Massachusetts. 
As a test object, the primary radicle of seedlings of Lupinus 
albus was used. The method of procedure consisted essentially 
in suspending the seedlings on glass rods for at least 24 hours in 
each experiment, in such a manner as to-immerse the radicles in 
the solution under study. In most cases the seedlings were under 
observation for 48 hours. At least four seedlings were used in 
each experiment of a series, and our deductions were drawn from 
the figures for average growth. With only a very few exceptions 
each member of the quartette manifested the same tendency. The 
solutions were carefully prepared from pure chemicals and were 
believed to be very accurate. The experiments were made in 
beakers, 
In order to get a basis for comparison, we made a number of 
solutions of different compounds of each of the heavy metals used, « 
* Read by title at the meeting of the Botanical Society of penaieks held at Wash: 
ington, D. C., December, 1902. 
7 Kearney, T. H., and Cameron, F. K. Some Mutual Relations between Alkali - 
Soils and Vegetation. U.S. Dep. Agric. Rep. No. 71. 1902. 
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