BY JAMES M. PETRI E. 545 



must play a primary part in those profound activities of the 

 protoplast, by which, in seasons of plenty, it is enabled to lay up 

 a large store of food-material, and to change it as required into 

 a form easily assimilated. We see the outward evidence of this 

 in the healthy, vigorous and rapid growth of the Giant Nettle-Tree. 

 Far from upsetting the balance and constituting abnormal 

 conditions (as sometimes happens in animal physiology) we find 

 the production of the excess of organic acid to be intimately 

 linked with the processes of dissociation and decomposition 

 which I have outlined above, and that together they conform 

 to the self-regulating mechanism of the plant metabolism. 



I here wish to express my indebtedness to Professor Anderson 

 Stuart, in whose laboratory the greater part of the work has been 

 done. 



REFERENCES. 



1. — Strasburger's Textbook of Botany, p. 98. 



2. — Roy. Soc. Queensland, 1885. 



3.— Bot. Zeit., 1882, p. 784. 



4. — Ameisensaure im Pflanzenreiche — Bergmann, J. 1883, 1392. 



5. —Jour. f. pract. chem. Bd.48, 191. 



6.— Dunstan and Henry, — Journ. Chem. Soc, 1898, T. 226. 



7. — Biochemical Journal, 1906, I., 1. 



8.— Harden,— Journ. Chem. Soc, 1901, p. 610. 



9.— Monatsh., 1895,211. 

 10. — Saussure, Rech. chem., 1804, 64. 



Pfeffer, Sitzber. d. Saeh. Ges. d. Wiss., 1891, 26. 

 11. — Landw. versuchs.-Stat., 1899, 195. 

 12.— C.R., 1901, 491. 



13.— Ber. d. Chem. Ges., 1879, Bd.xii., p. 753. 

 14.— Journ. Chem. Soc, 1901, p. 386, 459. 

 15.— Flora, 1886, p. 15. 

 16.— Bull. Soc Chem., Paris, 1901, 427. 

 17.— Proc. Roy. Soc. Lond., Vol. 77, B. 51S, Mar. 27th, 1906. 



40 



