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Vol. XXV, No. zt 
(4) The concentration of titratable acid was always higher in the juice 
of the leaves than in that of the stalk regardless of the plant's vigor. 
The hydrogen-ion concentration was higher in the leaves than in the 
stalk in the vigorous plants only; in the stunted plants it was greater 
in the stalks than in the leaves. 
(5) In the slow-growing plants of the most stunted plot, the titratable 
acid concentration of the stalk was at least one-half that of the leaves; 
in the vigorous rapidly growing series this ratio was one-third or one- 
fourth and occasionally even lower. 
(6) The specific gravity of the Juice of the leaves was always higher 
than that of the Juice of the stalk regardless of the plant's vigor. 
(7) Environmental conditions produced far greater variations in the 
acidity oi plants of the same strain than were ever found between plants 
of different varieties in the same environment and of equal vigor. 
LITERATURE CITED 
(1) Arndt, Charles Homer. 
192*. THE GROWTH OP FIELD CORN AS AFFECTED BY IRON AND ALUMINUM SALTS. 
In Amer. Jour. Bot., v. 9, p. 47-71* 6 fig., pL 4. Bibliography, p. 
70-71. 
(2) Arrhenius, O. 
1922. HYDROGEN-ION CONCENTRATION, SOIL PROPERTIES AND GROWTH OF HIGHER 
plants. In Ark. Bot., Bd. 18, p. 1-54. Literature, p. 41-52. 
(3) Bauer, F. C.„ and Haas, A. R. C. 
1^22. THE EFFECT OF LIME, LEACHING, FORM OF PHOSPHATE AND NITROGEN SALT 
ON PLANT AND SOIL ACIDITY, AND THE RELATION OF THESE TO THE 
FEEDING POWER OF THEPLANT. In Soil Sci., V. 13, p. 461-477, 8 fig., I 
pi. References, p. 477. 
(4) Bryan, O. C. 
193a. EFFECT OF DIFFERENT REACTIONS ON THE GROWTH AND NODULE FORMA¬ 
TION OF soybeans. In Soil Sci., v. 13, p. 271-287,15.pl. References, 
p. 285-287. 
(5) Clevenger, Clinton B. 
1919. HYDROGEN-ION CONCENTRATION OF PLANT JUICES. I. THE ACCURATE 
DETERMINATION OF THE HYDROGEN-ION CONCENTRATION OF PLANT 
JUICES BY MEANS OF THE HYDROGEN ELECTRODE. In Soil Sci., V. 8 , 
p. 217-226, i fig. References, p. 226. 
(fy '■ 
1919. HYDROGEN-ION CONCENTRATION OF PLANT JUICES. II. FACTORS AFFEC¬ 
TING THE ACIDITY OR HYDROGEN-ION CONCENTRATION OF PLANT JUICES. 
In Soil Sci., v. 8, p. 227-242, 1 fig. References, p. 241-242. 
(7) Duggar, B. M. 
1920. HYDROGEN-ION CONCENTRATION AND THE COMPOSITION OF NUTRIENT 
SOLUTIONS IN RELATION TO THE GROWTH OF SEED PLANTS. In Ann. 
Mo. Bot. Card., v. 7, p. 1-49, 7 fig. Bibliography, p. 47-49. 
(8) Haas, A. R. C. 
1920. STUDIES ON THE REACTION OF PLANT JUICES. In Soil Sd., V. 9, p. 34 
368, 11 fig., i pi. References, p. 367-368. 
(9} Hixon, Ralph M. 
1920. THE EFFECT OF THE REACTION OF A NUTRITIVE SOLUTION ON GERMINA¬ 
TION AND THE FIRST STAGES OF PLANT GROWTH. Meddel. K. Svenska 
Vetensk. Akad. Nobel Inst., Bd. 4, No. 9, 28 p., 12 fig. Literature, 
p. 26-28. 
(10) Hoagland, D. R. 
1918. THE RELATION OF THE PLANT TO THE REACTION OF THE NUTRIENT SOLU¬ 
TION. In Science, v. 48, p. 422-425. 
(11) Hurd, Annie May. 
1923. HYDROGEN-ION CONCENTRATION AND VARIETAL RESISTANCE OF WHEAT 
TO stem RUST and other DISEASES. In Jour. Agr. Research, v. 23, 
p. 373-386. Literature cited, p. 383-386. 
