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Vol. XI, No. 7 
several days. If the increase in permeability is not so severe as to cause 
the death of the tissues, recovery is followed in many cases by a rate 
of growth and of fruit production (in the tomato) in excess of the normal. 
Hence, in greenhouse practice it is unwise to condemn injured plants 
too quickly. The stimulation of growth may be due to at least two 
factors—namely, to the increased activity of the catalase which Zieger 
(26) found to be proportional to general metabolic activity in animals, 
and to the increased permeability of the cell walls, allowing readier 
exchange of food materials and of gases. It is very improbable that the 
extra nitrogen of the cyanid has anything to do with increased nutrition, 
as is suggested by Woodworth (25) in the case of scale insect eggs. 
In short, then, the primary effect of the presence of hydrocyanic add 
in a plant is a disturbance of the oxidase and catalase activities. All 
other physiological effects appear to be secondary to these. 
LITERATURE CITED 
(1) Alsberg, C. L., and Black, O. F. 
1916. the separation op autogenous and added hydrocyanic acid prom 
certain plant tissues and its disappearance during maceration. 
In Jour. Biol. Chem., v. 25, no. 1, p. 133-140. 
(2) ApplEman, C. O. 
1915. relation op catalase and oxidases to respiration in plants. In 
Md. Agr. Exp. Sta. Bui. 191, 16 p., 2 fig. Literature cited, p. 16. 
(3) Armstrong, H. E., and Armstrong, E. F. 
1910. the origin op osmotic effects, ni. the function of hormones in 
stimulating enzymic change in relation to narcosis and the 
phenomena op DEGENERATIVE and regenerative change in living 
structures. In Proc. Roy. Soc. London, s. B, v. 82, no. 559, p. 
588-602. 
(4) - 
1911. THE ORIGIN OP OSMOTIC EFFECTS. IV. NOTE ON THE DIFFERENTIAL SEPTA 
IN PLANTS WITH REFERENCE TO THE TRANSLOCATION OF NUTRITIVE 
materials. In Proc. Roy. Soc. London, s. B, v. 84, no. 571, p. 
226-229. 
(5) Budgett, S. P. 
1898. ON the similarity OF STRUCTURAL CHANGES PRODUCED by LACK OP 
oxygen and certain poisons. In Amer. Jour. Physiol., v. 1, no. 2, 
p. 210-214, 9 fig. 
(6 ) Bunzel, H. H. 
1914. a simplified and inexpensive oxidase apparatus. In Jour. Biol. 
Chem., v. 17, no. 3, p. 409-411, 1 fig. 
(7) Pezani, S. 
1913. SUL COMPORTAMENTO DELL* ACIDO CIANIDRICO INlETTATO NELLE PLANTE. 
In Arch. Farmacol. Sper. e Sci. Aff., v. 16, fasc. 12, p. 539-546. 
(8) Ewart, A. J. 
1896. on assimilatory inhibition in plants. In Jour. Linn. Soc. [London], 
Bot., v. 31, no. 217, p. 364-461. 
( 9 ) — 
1897. FURTHER OBSERVATIONS UPON ASSIMILATORY INHIBITION. In Jour. Linn. 
Soc. [London], Bot. v. 31, no. 219, p. 554-576, 1 fig. 
