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AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
briefly restated. Its adequacy at the present stage of experimentation is 
confirmed. 
2. The metals which form the bases of nutrient salts, as hydroxides 
and as chlorides and nitrates, are found to increase the hydration capacity, 
or the water deficit of the principal components of biocolloids, and of 
biocolloids of certain composition. 
3. Biocolloids containing soaps show a high degree of sensitiveness to 
hydrogen ions, or acidity. Such biocolloids show marked action in balanced 
solutions of sodium and calcium as shown by data too detailed to be given 
in this paper. 
4. Yeast vitamine water-soluble B, in a solution slightly acid, increases 
the swelling, hydration, or water deficit in some living and dead plant cell 
masses, and lessens it in others. Similar diverse action on biocolloids was 
found. 
5. All of the substances tested which are known to facilitate growth in 
plants are found to increase hydration capacity or water deficit in some of 
the test objects. The list includes chlorides and nitrates of sodium, 
potassium, magnesium, and calcium in various concentrations between 
0.001 N and 0.0001 N, glycocoll, alanine, phenylalanine, histidine, and 
water-soluble B yeast vitamine. Hydroxides of sodium, potassium, lithium, 
rubidium, calcium, ammonium, and aniline also increase hydration values in 
some of the components of living matter. 
